Slay Study
by secooper87
Summary: In Sunnydale, 1999, the Doctor teaches Buffy math whilst trying to solve a mystery. Twelve years later, in 2011, Buffy's troubles from 1999 suddenly reappear... but this time, things seem far, far worse...
1. Chapter 1

Author's Note: A cute story. It took me forever to write. I think you'll like it, though. There are some beautiful scenes - and some scenes that just make me laugh.

In terms of timing, I'd say the 1999 sections are set before Paradox but after Buffy's 18th birthday. The 2011 scenes take place in 2011 (we're talking Alison Korjensky here, so there's no time travel involved). It should be read after "Reunion". It does mention a few other stories which I hope to write some day but have not yet. I'm a little short on writing time. I'm doing my best.

Forgive the slight unevenness in chapter lengths... especially at the beginning...

Enjoy!

* * *

 **Sunnydale, 1999**

Wind gusted, as rain drenched the streets of Sunnydale. Lightning flashed in the distance, followed by a deafening roar of thunder.

"Nothing like a good rain, now and then, is there?" shouted an English-sounding voice, as he ran through the streets, waving about a blue-tipped sonic screwdriver. He kept buzzing, then adjusting it, then buzzing, again.

Lightning flashed, once more.

"Ooh! Didn't like that, did you?" the Doctor said, trying another frequency. The sonic chirped, then pulsed rhythmically. He beamed. "Ha! Got it!"

He spun 'round a corner. Kept sprinting.

"Not there," the Doctor said, swinging his sonic in different directions. "Not there… not there…."

Another flash of lightning. Another crash of thunder.

Then, suddenly, the entire area around the Doctor glowed blue, and a brick wall at the back of a nearby alleyway rippled with purple-blue energy. The brickwork on the wall began turning translucent.

"Oh, yes!" The Doctor sprinted over to the wall. "Yes. Yes! Brilliant." He soniced the wall, yet again. "Come on!"

The wall tried to reassert itself, fighting back against the sonic — but the Doctor adjusted the sonic while still buzzing, trying to stay on the offensive.

"Whoever set this up was good," the Doctor said, as the wall fought back — and he had to adjust the sonic, again. "But, know what?" His eyes twinkled. "I'm better!"

The wall began to convulse.

Splashing footsteps ran up behind the Doctor. Then stopped. "Doctor…"

Quick glance. "Bit busy, can you…?" He trailed off, as he noticed the gun now pointed in his face. "Ah." He raised up his hands. "All right, all right. I'll stop."

The gun lowered, a bit.

"Or maybe... I'm just getting close!" the Doctor cried, spinning back round and buzzing the wall, again. It convulsed even more, as a crash of thunder shook the ground beneath their feet. "You won't shoot. You wouldn't dare…!"

Lightning struck the building nearest them, filling the Doctor's vision with a blazing white light.

Then a gunshot rang through the air.

The Doctor fell to the pavement, bleeding, as his world faded into blackness.


	2. Chapter 2

**Several days earlier**

"...I go all with the dividiness," Buffy said, kicking the big-horned, gnarly-toothed demon in the gut, "and get… um…"

The Doctor poked his head out from behind the complicated gadget he was constructing, taking the sonic out from his teeth. "X²…"

The gnarly-toothed demon roared and punched at Buffy. She ducked, then grabbed up a nearby metal trash can and slammed it over the demon's head. "Okay, okay… x² + 50x + 2 equals..."

Clawed hands wrapped around the can, as the demon wrestled Buffy for it.

The Doctor soniced his gizmo, which spluttered into life. "Equals?"

The demon, with a roar, crumpled the trash can and tossed it aside. Swiped at Buffy — who dodged both claws and can, then threw herself at the demon, giving it a great big shove. "249!"

An illuminated open door sprung up from the Doctor's machine.

The demon didn't catch itself in time, and gave another roar as it skittered right through the door. The Doctor darted forwards, yanking a wire from the gizmo. Doorway and monster vanished. "43."

Buffy blinked. "Huh?"

"Not 249," the Doctor explained, swiftly dissecting his gizmo and pocketing the pieces. "243."

Buffy sighed. "I'm never going to get this."

"Nah, it's easy!" The Doctor pocketed the last part of the gizmo, then took out a piece of chalk and wrote out all the steps on a nearby blank wall. "See? Carry the four, and… 243!" He rapped his knuckles against it. "Now, it's just a regular old giraffe."

"Giraffe?"

"Polynomial," the Doctor corrected. "Sorry, brain reached for the wrong word there. Regular old polynomial!" He rapped his knuckles, again. "Easy peasy!"

Buffy studied the math. She still didn't feel any better about her big test, tomorrow.

On the street beside them, a group of teenagers stopped a car blaring loud music at a red light.

The Doctor noticed Buffy's despair. "Oh, come now! It's not so bad!" He beamed. "Bit of positive thinking — and you'll be right as ninepence. Worked for my TARDIS driving test!"

"I thought you said you failed that," Buffy said. She crossed her arms. "Twice."

The Doctor scratched the back of his head. "Well… twice-ish."

Buffy shot him a look. Then sighed and traced her fingers along the mathematics on the wall. "It all makes sense, I guess. I just…" She grimaced. "I dunno if I could come up with that, myself."

"Course you could," said the Doctor. "It'll be second nature to you. Like riding a bike! Or staking a vampire!"

Buffy just kept staring at the numbers on the wall.

"Tell you what," the Doctor offered, shoving his hands into his pockets. "Take the exam, tomorrow. See how you do. And if you need a bit more help…" He tossed her a small key — which she caught. "...drop by the TARDIS and I'll find you another study-monster."

Buffy stared between him and the key. "You're sticking around?"

The Doctor shrugged — then grinned at her and winked.

Buffy grinned back, tucking the key into a pocket.

Then she said her goodbyes and headed off.

The moment she left, the Doctor raced out to the car that was still blaring music, in the middle of the street. The light was now green, but the car was still there.

But empty.

The Doctor spun around, and headed to the car behind it. Same thing. He ran to the car behind that one. Same thing!

"Everyone's just vanished," the Doctor said. "Poof! Gone. Except, if they'd _actually_ just vanished in a puff of smoke, these cars would be moving. Unless…" He examined the brake pedals. Each was still held down, as if being pressed by an invisible foot. "Oh. Now that's interesting." He scratched his head, intrigued. "Yep. Buffy Summers — it seems I really will be sticking around."


	3. Chapter 3

Author's Note: I did a summer abroad at Oxford, back in college. This is exactly how I remember the tutorial system working. You'd think a system without tests would be easier, but it's way harder. Every tutorial is like a mini oral exam, and there are extra research assignments you wind up doing, just kind of because! Anyways, I tried to write this to be true to what I remember. True, I didn't do computer science... but I figure if some guys in China studying nanotubes had to read Homer when they created what they called the "Trojan Catalyst", you could imagine there might be a weird scenario in which this would come up for Alison.

Besides, I wanted Buffy to talk about Vikings. I was enjoying it.

Enjoy!

* * *

 **Twelve years later — Oxford, 2011**

Alison Korjensky raced after the skittering silver lizard alien, trying to leap on it — but failing, as it scuttled into the sewer.

Buffy grabbed the nearest pole-looking thing, and ran off. "Manhole cover… that-a-way. Come on!"

Alison sighed. "You do realize I have a tutorial, tomorrow? Vikings! History! That sort of thing."

"I thought you were studying computer science," Buffy said, glancing over her shoulder.

Alison raced after Buffy, back to the main street. "Yes, well, the course isn't actually on Vikings," Alison replied, in a bit of a huff. "But at the last tutorial, I said something that led to Molly saying something that led to the tutor saying a lot more somethings — and, long story short, the tutor asked me to research pretty much all of Viking history and then present a paper on it tomorrow."

Alison and Buffy emerged onto the main street, where they discovered that all the traffic had randomly stopped — for no apparent reason — and everyone was now deathly silent, shuffling like zombies.

Alison slowed. Then stopped. "Unless… they're suddenly undead…"

One of the zombies looked at her, blankly. Then, for no apparent reason, it just vanished into thin air — pop! Right before Alison's eyes!

Alison yelped.

Buffy saw it, too. Slowed and sighed. "Oh. Great. I guess I should have expected this." She shook her head, as another person vanished. "Okay. Let's put that aside and work on the more important thing — catching the alien lizard scout before it reports to its superiors." She scanned the road around her. "Sewer-dar… sensing manhole cover…" Buffy spun around, pointing. "There!"

Alison wasn't sure why Buffy thought the alien was their top priority, instead of the disappearing zombies, but Buffy was usually right about these sorts of things…

Alison sprinted after her, as Buffy ran to the manhole cover.

"That some Slayer superpower?" Alison asked, as Buffy yanked the manhole cover off the sewer. "Extreme sewer-sensing-skills?"

"If it's not, it should be." Buffy began descending the ladder. "Significance of the Viking raid at Lindisfarne monastery?"

Alison blinked, as she followed Buffy down. "Sorry?"

"The importance of the Viking raid at Lindisfarne was…?" Buffy jumped down, grabbing a flashlight out of her back pocket and shining it around. "Come on. I thought you said you were presenting a paper on this stuff tomorrow."

Alison slid down the ladder, the rest of the way. "Yes, but… _now_?" Shook her head. "You're kidding."

Buffy shot her a look. Then, spying something out of the corner of her eye, raced forwards, pursuing the alien.

"Or you're barmy," Alison muttered, running after her. To Buffy, "In 790, Vikings attacked Lindisfarne monastery, and medieval blokes were all real religious and thought churches were safe, so it made them feel terrified and vulnerable."

"793, not 790. June 8, to be exact. Tuesday." Buffy sprang at the alien, grabbing it and struggling to keep hold of it, as it writhed in her hands. "And it was important because that raid interfered with a ceremony the monks were doing to stop the Lindisfarne Hellmouth from opening."

Alison blinked. "Sorry?"

"Tranq gun!" Buffy shouted, as the alien squirmed.

Alison grimaced, grabbing up a small gun from her side and shooting the alien creature in Buffy's arms. "Hellmouths aside, how do you know the precise date of…?"

"My daughter decided to treat me, on one of my birthdays, by taking me to the Birthday Planet," Buffy said, as the alien creature went limp in her hands. "Guess where we wound up landing, instead?"

Alison's jaw fell open.

"Come on," Buffy said, slinging the alien over her shoulder. "We'll go all hackey on the CCTV cameras to figure out where this lizard-scout came from, before Oxford winds up swarming with them. We can slay-study on the way." She ran past Alison, back to the ladder to the manhole. "Sticking to the north — how did the Vikings' eventual settlement in York affect the economics of the British Isles?"

Alison grumbled, as she followed Buffy. "Not all of us have Slayer-skills that mean we can multitask while fighting aliens, you know."

Buffy gave Alison a hand, pulling her up out of the sewer. "Hey, I dropped out of college and flipped burgers for a living," she said. "If even _I_ know this stuff, you've got no excuse." She spun back around, and ran off. "So economics me!"

* * *

 **Twelve years earlier — Sunnydale, 1999.**

"So?" said Willow, strolling down the hallway. "How was the big test, last period?"

"Weirdly okay-ish," Buffy admitted. Put a hand up to her head, with a small smile. "Freaky thing was, when I was going all pencil-scribble on the trig stuff, I could picture working out all the math steps just the same way I picture working out all the fighting steps to take down a big bad." She turned to Willow. "Is that what it's like to be all with the Willowness?"

"No… I think Slayer-math is more a Buffy-ish thing," Willow corrected. She stopped in place, staring. "And speaking of weird Buffy-ish things…"

Buffy turned. Then sighed.

The Doctor was wandering down the hall, using his sonic to unlock every single classroom door, in turn, and fling it open. He scanned the sonic up and down, inside the classroom — and shut the door. Then moved on to the next door.

Buffy went to the 5th door along — this classroom occupied and class in progress — crossed her arms and leaned against it. The Doctor raced onwards. Saw her. Then slowed and stopped.

"Oh," he said, a bit sheepish. "Hello! Sort of… thought you'd be in class, right now." He scratched the back of his neck. "Exam go all right?"

"It went okay," Buffy said, "and I've got a free period."

"Free period?"

"As in I'm cutting class," Buffy admitted, "so now it's free. What's with the sonicyness?"

"What? No! Nothing! No sonic!" the Doctor insisted, holding up his hands to illustrate. Then remembered he was still holding the sonic. "Well, now that you mention it…"

"More like big on the somethingness?" Buffy guessed.

The Doctor winked. Then pushed past her and yanked open the door to the classroom. "There! See?" Raced inside. "Knew I'd find one."

Buffy sighed and darted after him, ready to drag him out while apologizing to the teacher. But when she walked inside the classroom… she froze.

The Doctor was waving his sonic at a piece of chalk floating in midair — still in the midst of writing "793 — Vikings invade Lindisfar…" on the blackboard. No hand held the chalk.

The teacher had vanished.

So had the students.

Buffy stared at the desks still strewn with papers and notebooks and pencils, the floor full of backpacks. She'd heard them in here. Seen them through the window in the door!

The Doctor checked the sonic for readings on the floating chalk. "Nothing!" Shook out the sonic. Checked again. "Nada! Zip! Zero! Zilch! Zulch! And shoemaker! It says everything's normal!" He circled the floating chalk, inspecting it. "So why…?"

"Buffy, is everything…?" Willow said, running into the classroom. She stopped, as she noticed the floating chalk and the abandoned desks and backpacks. "What the…?"

"So say we all," said Buffy. She turned back to the Doctor. "What's with the Pompeii-ness? Are we talking demon? Mystic spell? Alien trying to conquer the world? Or is this just your average Hellmouth opening apocalypsiness?"

The Doctor tried scanning the chalk, again. Checked the sonic. "Not a clue! Sorry."

Someone else appeared in the doorway. "Hey, I heard Willow's voice," said Oz, leaning in, both hands on the doorframe. "What's…?"

He stopped and stared at the classroom.

The Doctor spun on Buffy. "Do _all_ your friends cut class?"

Willow coughed, pointedly. "Hey! _I_ have math, this period," she announced, proudly, "and when I finished the test in only 30 minutes, I was allowed to leave early. Which means I'm here legally!"

"Yeah… not so much for me." Oz nodded at the classroom. "So… what happened? Chalk levitation spell gone wrong?"

"Not far as I can tell," the Doctor said, turning and walking in between the desks. He paused, examining a pencil that was still scribbling down notes, seemingly unaware that the hand holding it had vanished — or that the lecture had stopped. "I would say that everyone here just vanished, but… thing is…" The Doctor plucked the pencil out of the air and it stopped writing. "It's more like the universe just sort of… glitched."


	4. Chapter 4

Author's Note: I'll just say that, after writing this, I really want to hear Buffy teach a history class. Come on, Great Courses Plus and TED Talks! Recruit this fictional character, already. You know the world wants it.

Enjoy!

* * *

 **Twelve years later — Oxford, 2011**

"No, no, no!" Buffy was explaining, as they ran into a local cafe. " _Lindisfarne_ is the one with the Hellmouth. York doesn't have a Hellmouth."

Alison, her laptop under her arm, looked about — but spotted no one. Odd. "Right…"

"York is just where the Slayer happened to live, back in the 9th century," Buffy explained, as Alison sat down at one of the tables and opened up her laptop — as Buffy ran about the cafe, looking to see if she could find any people. "I summoned her spirit, back when I had to defeat the resurrected, demonified remains of Ivar the Boneless."

Alison began typing, hacking the cameras — but she couldn't help a smile. "You really are mad. You know that?"

"What's important, economically," Buffy said, as she snuck back behind the pastry display, to glance in the kitchen, "is that the Vikings developed really extensive trade routes from York, after settling there." She found no one, and headed back. "Which is why the charm I needed to summon the spirit of the Slayer and destroy Mr. Demonified Boneless-guy was buried in Southampton." She began pacing the cafe, restlessly. "You hacked those cameras, yet?"

"Oi! Give me a chance!" Alison protested, not pausing in her typing. "I'm trying to listen to stories of Slayers and Hellmouths and Vikings, while hacking the supposedly-unhackable CCTV cameras about town — and, what with Torchwood being gone, that is not easy!"

Buffy ran hands through her hair. "Lots of things would be easier if Torchwood were still around." She yanked out her phone and scrolled through the contacts menu. "Good news is — we've still got Giles' books."

Alison glanced back at Buffy. "You're calling _Giles_ , to help me learn Viking history?!"

"Nope, this is for the lizard-help." Buffy selected Giles' number, and pressed the phone to her ear. "Can't go wrong with Giles."

"Right… so you're calling up Giles, on the off chance his books have some sort of prophecy on this?" Alison scooched a pantomime pair of glasses up her nose and put on a Giles voice. "On the fourth week of the Michaelmas full term, a wayward soul shall sacrifice to a demon, and lo, there shall be many zombies, and all the weird-looking lizards shall scuttle about, not doing much of anything."

Buffy gave Alison a half-smile. "Not a bad Giles," she said. Shrugged. "Still — don't knock the Giles-bookiness. It's how I survived high school." She frowned, looking down at her phone. Selected the number again. And waited. "No answer." Spinning around, suddenly, for no apparent reason, she ran out of the cafe. "Be right back!"

Alison sighed, returning to her hacking. "Sort of wish I could have seen you back in school in Sunnydale," she muttered, as she typed. This legendary, insanely clever, utterly impossible woman? In school?

Wonder what _that_ would have been like!

"Probably a bit like Seo," Alison muttered, as she kept up her typing. "Except with fewer explosions."

A sniff, from her right. " _I_ didn't blow up _my_ school." The voice paused. "Although… come to think of it… why _didn't_ I blow up my school? That would have been brilliant!"

Alison nearly jumped a mile high, at the voice. She glanced over her shoulder, and broke out into a relieved smile.

"Seo!" Alison cried, grabbing her into a hug. "You're a git, you know." Pulled out of the hug, glaring. "Away for months — and not even a postcard?!"

That was when Alison noticed that Seo wasn't exactly her usual self. She seemed nervous. Shaken. Eyes haunted, hands trembling…

Alison put her hands around her friend's, to steady them. "You all right?"

Seo, at first, didn't even seem to register that Alison had asked a question. Then, she blinked. "What? Oh. Yes. Fine." She yanked back her hands and shifted from foot to foot. Her eyes drifted out to the front of the cafe. "Jenny's here, too. Outside. Remember her?"

"I remember Torchwood, Ethan Rayne — and you punching through solid steel." Alison grinned. "How many walls you punched through on the TARDIS, so far, while traveling about with her?"

Alison was expecting a quip from this.

Instead, Seo didn't say anything. Her eyes remained fixed on the figures of her mother and Jenny, visible through the cafe windows.

"You're not all right at all, are you?" Alison asked. She put a hand on Seo's shoulder. "What happened? I thought you were running about the universe, making mischief with Jenny and the…"

"He's gone," Seo said, without looking at Alison. She forced down her fear, and sat down at the table by Alison's computer, turning it around so she could take over hacking the cameras.

Alison sighed. "And here I was, thinking this'd be a nice, normal day with aliens and a zombie apocalypse." She pulled up one of the other chairs, and sat right beside Seo. "Is he in trouble? Is it our turn to do the cavalry thing?"

"He's… just…" Seo hesitated, her fingers pausing in her typing. She glanced over at Alison. "Gone. Just… gone."


	5. Chapter 5

Author's Note: I had someone comment, "Oh, no, a glitch. Please no Matrix!" Well... here's your Matrix! The Doctor mentions Majorana fermions. The basis for these particles comes from imaginary gamma matrices that produce a real result! See? Matrix!

I guess if you take the red pill, you actually just wake up at CERN or something, studying particle physics...

Anyways! Enjoy!

* * *

 **Twelve years earlier — Sunnydale, 1999.**

"Glitched?" Buffy said, as they all exited the classroom and ran down the hall. "What do you mean 'glitched'?"

Willow beamed. "You mean like a computer! Right?"

The Doctor spun around, running backwards so he could point at Willow. "Bingo-bongo-bango! Got it in one."

"Um… huh?" Buffy asked.

The Doctor almost tripped over a trash-can while running backwards — and Buffy grabbed him by the arm, pulling him upright before he could topple to the ground. He winced, hand to his head. Spots briefly danced before his eyes.

"Like glitchy computer games," Willow insisted. "The people disappear, but the pencil's still been programed to wiggle around and take notes. So you get, like, floating chalk and pencils that keep scribbling notes and all kinds of other weird stuff."

"Like floating candybars?" Oz asked, noticing the candybar hovering in midair beside the vending machines. A bite had been taken out of it.

Eyes glowing with curiosity, the Doctor zipped over and scanned it with his sonic. Checked the readings. Then gritted his teeth. "Still — nothing! Says it's normal!" He tried scanning it again, but it didn't help. "Doesn't make sense."

A scurry of footsteps raced towards them — and Xander appeared at the other end of the hall. "Hey, guys! Cutting class? Count me in." He ran over, then grabbed the candybar out of the air. "Oh, hey! Free chocolate."

Buffy yanked it out of his hand. "Xander, we were studying that."

The Doctor had stopped studying it, though. Instead, he was examining the Scoobies. "And that's another thing that doesn't make sense," he muttered. Spun back to Buffy. "This _is_ 1999, yes?"

Xander, deciding that they were now officially _not_ investigating the candybar, grabbed it back from Buffy and took a bite.

"Either that, or everyone's calendars have been wrong for over a month, now," Oz put in.

"Why?" Willow asked. "Is that important? Is there a prophecy about February, 1999, or something?"

The Doctor scanned his eyes across the crowd of Scoobies, all strangely friendly towards him — and not hostile in the slightest. Odd, that. The Doctor was pretty sure that Buffy's friends really didn't like him, at this point in history.

Buffy, as if reading his thoughts, cut in. "I… uh… had a talk with them. They've agreed to go all with the supportiveness for now."

"As I recall," Xander said, waving the candybar at her, "you said that if we were nice to the Doctor — you'd bake us all cookies for, like, a week." He took a bite. "And you won't see me turning down cookie-week."

The other Scoobies all shuffled, a little shame-faced. It appeared they'd also been taken in by the lure of cookie-week.

"Well," the Doctor sighed, running a hand through his hair. "Suppose that answers that. Wonder what I do to get you lot dead-set against me, after this." He glanced at Buffy. "Might be she burns the cookies."

Willow shoved her hands on her hips. "Hey! That is _not funny_ , Mister! Cookie murder is very serious!"

The Doctor sighed, dropping the subject. "Doesn't matter." He spun around and ran off. "After all, people are disappearing without any giraffe or reason, and yet — no, sorry. Not giraffe. What's the word for…?"

He stopped, as he realized no one was following him. Spun back around, and noticed that Buffy and the Scoobies had been accosted by a short, scowling man in a business suit.

The Doctor sighed. Brilliant. Principal Snyder.

"...a bunch of class-cutting hoodlums," Principal Snyder was lecturing them. Pointed his finger in Buffy's face. "And you, Miss Summers, are the worst. Your mother is very concerned about you, young lady. She wants you to study, right now — or she'll…!"

The Doctor rushed over to the confrontation, yanking out his psychic paper. "Sorry about this. Bit of a mixup." He handed Snyder the leather wallet. "Dr. John Smith, Department of Education, Washington DC. Just thought I'd borrow these students for a…"

Snyder opened the wallet and glanced at it. "It's blank."

The Doctor frowned. "Is it?" He yanked the wallet out of Snyder's hands. Grimaced. "Well, that shouldn't happen."

"What is this?" Snyder demanded. "Some kind of joke?" His eyes narrowed. "You a drug dealer or something, coming into my school to push some serious…?"

"Nope!" The Doctor tucked the psychic paper into a pocket. "Actually, just here to understand and stop a very troubling phenomena in the fabric of the universe — one which could leave you floating about as disassociated atoms, and has already…"

"He's my physics tutor," Buffy cut in, hurriedly.

Snyder looked between the two of them. He clearly didn't believe her. "Physics tutor."

"Yeah, well, I mean, just listen to him," Buffy insisted. "He's, like, all with the atoms and universes and… nonsensical outer-spaceyness."

"Nonsensical?" The Doctor gave a huff. "Me? _You_ lot are the ones still spouting all that rubbish about string theory and loop quantum gravity! I mean, honestly, if you analyze a Majorana Fermion in a…"

"Okay, okay, he sounds legit," Snyder admitted. Then, taking the Doctor aside, added, "Although, if you ask me…" glanced back at Buffy. "...tutoring that one?" Shook his head. "Waste of time. Total idiot."

The Doctor quirked an eyebrow. "She's clever, engaged, eager to learn — and exceptionally bright. How's that make her an idiot?"

"Ask her teachers, and they'll tell you the truth," Snyder insisted. "They all agree: she's a troublemaker, a delinquent, and a dunce."

The Doctor shrugged. "Suppose that just means you've hired rubbish teachers." He winked at Buffy.

"Hey, if you want to try to tutor her, be my guest! Just don't come crying to me when she fails her tests and beats you up so she can steal your wallet." Snyder glared at her, over his shoulder. "I've seen kids like her, before. I know the signs." His cold eyes met Buffy's. "Ten years from now, she'll be in a maximum security prison, doing hard time while toting serious drugs." He flicked his eyes over to the Scoobies. "And her two friends will be there, beside her."

" _Two_ friends, huh? Just me and Oz?" Xander elbowed Willow in the side. "Guess you just made Snyder's Student-of-the-Month club, Will."

The Doctor, hearing Xander's words, glanced at the Scoobies — and his face fell. "Ah," he said, sadly. "Two friends."

Buffy spun around, following the Doctor's line of sight. So did the other Scoobies. They stared. Buffy's jaw dropped. Xander choked on his candybar. Willow's eyes went wide — and then she screamed.

There, hovering in midair beside them, was Oz's backpack.

That was it.

Oz was gone. Just… gone.


	6. Chapter 6

**Twelve years later — Oxford, 2011**

The cafe door burst open and Buffy entered, her arm around Jenny. Unlike Seo, Jenny wasn't jittery or scared. More sort of… in a state of shock.

"Okay, the Doctor's 'just gone'," Buffy said, easing Jenny into a chair. "I get that." She stepped back, crossed her arms — eyes fixed on the sisters. "What do you two remember?"

Jenny and Seo looked at one another.

Then both looked away, hurriedly. Said nothing.

Then, after a minute, Jenny sighed. "We… don't know what happened. We were in the TARDIS console room, not doing much of anything, when it all went… a bit funny."

"Funny… how?" Alison asked.

"The air," Seo muttered, "tasted… strange. Everything started to blur."

"And then the console sparked," Jenny added. "And a repeating gong sound filled the whole TARDIS."

Buffy absorbed this all with a slow nod.

"Father started shouting," Seo said, softly. She had stopped typing — her hands shook too much. "He looked furious."

"He kept insisting that this was impossible — it was all completely impossible," Jenny explained. "He said the TARDIS was giving him readings that didn't make sense. Then he kicked the console. Then he stubbed his toe. And then…"

Jenny trailed off.

"Then?" Buffy asked.

"Then he was gone," Seo whispered, the shaking in her hands and arms and entire body growing worse. She was starting to hyperventilate. "Just… gone."

Alison remembered the people on the street who had vanished in front of them. Had that happened to the Doctor? Was that what she meant?

"Seo remembers better than me," Jenny told them. "From my perspective, one minute, Dad was kicking the console, and the next, I was wandering down a street in Oxford. Seo was here. Dad was not." She gestured at Seo. "Seo looked panicked. I asked her what had happened, and she said Dad was just… gone." Grimaced. "Neither of us know how we got here. I don't think we ever landed."

"Sorry, you didn't land?" Alison glanced between the two. "You mean, one moment, you were out and about in time and space, and the next moment… you found yourselves in Oxford?"

"I… I just…" Seo stammered. She shuddered, huddling into her chair. "I don't know what happened. Father was furious, kicking the console. Then he was gone. Then everyone was gone, and I was alone, and…" Her eyes grew even more terrified. "I don't know. I found myself here."

Buffy came over and sat in the chair beside her daughter, patting her back soothingly and comforting her. Seo relaxed a little — but kept staring into the distance, her whole body still shaking.

"And you remember nothing about Angel?" Buffy checked with Seo. "Hypercubes?" She flicked her eyes up to Jenny. "Silver lizards?"

Jenny blinked, frowning, then shook her head. Seo also shook her head — perhaps less convincingly.

"Ms. Summers," Alison cut in, sharply, "do _you_ know something about all this?"

Buffy snapped her eyes over to Alison. "Who? Me? I'm not all with the outer-spacey." She sighed, rubbing Seo's back, her face bent in intense thought. Then Buffy winced, as if something had hurt her — and jumped to her feet, running towards the cafe windows.

Outside, swarming down the street in front of the cafe, was a seemingly endless stream of silver lizards. Alison had no idea where they were headed.

Buffy swore beneath her breath. Then she staggered, in pain again, but caught herself on a bistro table.

"You guys have to get somewhere safe," Buffy decided, turning back to them. "Wherever that might be." She gritted her teeth. "I was hoping that Giles would be here when this happened. I thought I'd have more time. But they're here, already — and Giles is definitely a no-show in the phone-pick-up department."

Seo just kept staring, blankly, in front of her.

Alison, putting an arm around Seo's shoulders, shot Buffy an accusatory glare. "You _do_ know something!"

"Alison, grab all the weapons you've got stashed away in your apartment," Buffy instructed, instead of offering a justification, "then find somewhere easy to defend and barricade the door. Don't let anyone in." She paused. Then added, "Unless they're Giles!" She turned back to the door of the cafe, and pushed it open, heading into the street. "I've gotta stop this, before it goes any further."

Alison leapt to her feet, running out of the cafe and after Buffy. "Any further?!" She grabbed Buffy by the shoulder and spun her around. "What's 'further'? What's this all about?"

Buffy shivered — and, with the shiver, her body began to fade into transparency. Alison gasped. Buffy squeezed her eyes shut, concentrating hard, and her body stabilized and became solid, once more.

"I can't…. There's no time," Buffy apologized. "I left Giles a voicemail. He'll help you. Promise." She shivered, again, barely managing to keep herself from fading into thin air. "Just… keep them safe. Defend them. Help Seo." She rubbed her own arms, as she kept shivering. "I love her more than anything, Alison. Make sure she knows that, in case I don't…"

Buffy stopped.

Then she shook her head, spun around, and ran off.

Alison began to run after her. "In case you don't… what? Come back?!"

"It's too much, Alison," Buffy called back, as she ran. "I'm sorry. I just — I can't control it. I thought I could, but I can't." She shuddered, rubbing her arms as if staving off a chill. Then, pointing at the cafe, added, "Defend them! And don't let them follow me; it's not safe!"

Then Buffy turned a corner, and left Alison's field of vision.

Alison's jaw fell open, as she slowed — unwilling to stray too far from where she'd left Seo and Jenny. Her mind spun, as she stood beside a stream of silver lizards.

"Defend the others," Alison said, to focus herself. She ran back to the cafe. "Yes. Right! Fine. I can do that. What could be easier, with Seo and Jenny for fighting help?"

She ran back inside the cafe, but paused in the doorway. Jenny had drifted into some sort of trance, drooping in her chair, her face turning zombie-like. Seo was still trembling and staring into space, disassociated with the outside world.

"Then again," Alison muttered, "perhaps help is overrated." She grabbed Jenny by the shoulders and shook her. Shouted: "Jenny! Silver lizards! Zombies! Get a hold of yourself, girl!"

Jenny blinked, then seemed to come back to herself. "Sorry, I… don't know what…" She put a hand up to her head, confused. Then noticed a napkin with a scribbled note left on the table. She picked it up.

"That's Jenny; now for Seo." Alison rushed over, sat beside Seo, trying to calm her trembling. Then, over her shoulder, added, "Jenny, please tell me that note's from Buffy, and that it contains some sort of explanation for all this."

Jenny didn't answer — just handed the note to Alison.

Alison looked it over.

"Jenny," Alison read aloud, "please ask Alison about Viking attitudes towards the adoption of bullion." She crinkled up the napkin and threw it at the far wall.

Then gave a wordless, angry shriek.


	7. Chapter 7

**Twelve years earlier — Sunnydale, 1999**

Buffy was grinning ear-to-ear, examining the small ring-looking thing with the huge gemstone. Giles' latest mystical amulet — found and obtained. Go Slayer-power!

The Doctor coughed, pointedly.

Buffy grimaced. "Oh, yeah… uh…" She furrowed her brow, thinking. "…28 miles per hour?"

The Doctor quirked an eyebrow at her.

"27?" Buffy tried.

The Doctor quirked the other eyebrow.

"I'm not close, huh?" Buffy slumped down onto a nearby gravestone, twirling the ring in her fingers. "Well, at least I got Giles' thing."

The Doctor opened his mouth to answer her, then… stopped. Spun about, taking in his surroundings. "Wait a tic. We shouldn't be studying. We came here to investigate the disappearances." He pointed at her. "You said we had to wait until night because we needed Angel's help." He scoffed. "Although I find _that_ laughable."

Buffy put the ring into her pocket. "What's with the whole you-Angel hostility thing, recently?"

"Sorry? Did you miss the bit about how he killed my friend Nadezhda back in 1898?" the Doctor asked. "And then there's 1860, of course — and the numerous irresponsible things he's done from a temporal standpoint, since he got back his soul and…"

"Yeah, but you're not usually all with the fighty bitter thing," Buffy put in. "Last time I asked, you said you forgave him."

The Doctor paused. Frowned. Scratched his head. "You're right. I did." He reflected. "Odd, that I didn't remember that." He stepped towards Buffy, his brow creased in thought. "Have I just gotten over a sort of traumatic brain injury? Something like that? Something bad enough that it nearly killed me?"'

Buffy looked at him, blankly.

"Doesn't have to be percussive injury," the Doctor offered. "A nervous breakdown, perhaps! Or could be I turned up looking blank and empty — bit like a zombie. Or…"

Still, Buffy seemed none the wiser.

"Or possibly not." The Doctor ran a hand through his hair. "When I arrived in Sunnydale, I didn't turn up looking like something had just happened to me? No injuries? Marks? Blood? Nothing?"

"You were just kind of all with the bubbly-excitement and brainy-specs," Buffy said. She noticed a small silver lizard skittering across the ground and staked it through the heart. Then hurried to cover it up so the Doctor wouldn't noticed she'd killed something. "I dunno. Why? Is it linked to the disappearances?"

The Doctor screwed up his face, as he thought it through. "I don't think so — unless every single one of my theories is completely off. But… well… might explain why my head's a bit muggy and why I'm reliving past resentments and emotional states. It's what happens when a Time Lord brain heals; old things come to the forefront."

A throat cleared, behind the Doctor. "So… does that mean you're going to kill me, or…?"

The Doctor spun around — to find Angel right behind him, looking a bit nervous but trying to hide it.

"What? Me? Kill you? Nah," the Doctor dismissed, waving his hand through the air as if swatting the suggestion away. "That sound like me?" He shoved a finger in Angel's face, before he could answer. "No, actually — don't answer that. I'm aware of your poor opinion of me, already."

Buffy ran in between them, keeping them apart. "He's been going all with the physics study, while we were waiting," she explained to Angel. "But now that you're here, we can investigate disappearing people."

With that, Buffy ran off — out of the graveyard and into the streets of Sunnydale.

Angel glanced at the Doctor, warily. "You're teaching her physics? Really? And she's just letting you?" He shook his head, then ran after Buffy, muttering, "She should know better. She's going to make herself miserable."

"Sorry? Should 'know better' than to try to learn?" The Doctor ran after the two of them, giving a frustrated sigh. "Well… then again, you said Nadezhda was thick as a bag of rocks — so clearly, you haven't the first idea what being clever actually looks like." He shot Angel a forced grin. "Sound about right, Angelus-be-dangelous?"

Angel bristled at the nickname. "You're just trying to annoy me, aren't you?"

"Me? Annoying and chatty? Perish the thought!" The Doctor whipped out his sonic screwdriver, and waved it about. Then called out to Buffy: "Wait a tic! Think I got something."

Buffy slowed and spun around. Started walking back, but stopped when Angel caught her by the arm.

"Don't do this, Buffy," he whispered to her. "Please. I know why you feel you have to, but you're only making this harder on yourself."

Buffy shook him off and walked over to the Doctor — who was checking the readings on the sonic. "What's up?" She leaned against a nearby picket fence. "You sonic up the answer, yet?"

"For a second… I thought that…" The Doctor scanned the air again, then checked the readings. "But nope. All back to normal. Odd, that." He scratched his head. "Very odd…"

Buffy shrugged, fidgeting a little awkwardly. "Odd like… how? I mean, would it help to talk about it, or… you know?"

The Doctor blew a breath out of his cheeks. "Suppose it couldn't hurt, but…"

"Buffy," Angel urged, coming up behind her. "Don't do this. Don't ask him to teach you. Please."

"Oh, well, in that case, 'spose I've got no choice!" The Doctor put away his sonic and grinned. "Right then! Physics. Let's start with the basics, then onto Einstein and Heisenberg, then Blinovitch and the quanti-temporal, and finally — Hellmouths and odd not-quite there energy signatures." The Doctor offered her a hand.

She took it.

And together, they ran down the street, further into the heart of Sunnydale — not even looking back, as Angel growled but trudged after them.

* * *

"Nah, you'll get it, eventually! Told you — physics is easy!" the Doctor insisted, still buzzing his screwdriver through the air as they strolled through a very crowded downtown Sunnydale. "You just need to see it for yourself." He analyzed the sonic, frowned, then tweaked a setting and tried again. "Physics isn't just chugging numbers through random equations, you know. It's all around us! All the time! Its same universal laws govern you, your atoms, your world, and the whole universe." He glanced over at her and winked. "Gotron-12! Utterly bizarre gravity in Gotron-12. After we've cleared up this mess with the disappearances, I'll take you there. By the time you come back, you'll understand gravity completely!"

Buffy sighed. "Slayer, remember? No outer-spacey stuff for Buffy."

"Besides, you're not leaving here, Doctor," Angel said, clearly irritated. He looked over at Buffy. "He can't, Buffy. You know he can't."

The Doctor quirked an eyebrow at Angel. "I can't?"

"Because I won't let you take Buffy away," Angel put in, a little too quickly. "I won't let you kidnap her."

The Doctor stuffed his hands into his coat pockets. "Remind me, Angel — what did you do to Nadezhda after you and your vampire associates kidnapped her?" He smacked his hand on his forehead. "Oh, that's right! I don't need to ask. You wrote her father a letter — in her blood — describing _all_ of it, just to rub it in all our faces!" He stepped forwards. "She _saved the world_. And you…!"

Buffy coughed, pointedly.

"Yes, right, sorry," the Doctor sighed, holding up his hands and stepping back. "Forgot. Forgiveness. Past is the past. All that." He paused a moment, thinking. "Perhaps that's it. Perhaps _I'm_ the reason the sonic isn't working." He examined the sonic. "If my head's still a bit naff, then maybe it's…" As if not seeming to notice he was doing it, the Doctor suddenly flipped into a smattering of different languages — none of which the TARDIS translated.

Angel crossed his arms, but said nothing.

Buffy came over to the Doctor and put a hand on his arm, cautiously. "You okay?"

The Doctor paused. Frowned. Then, in English, said, "Language center of the brain. Bit scrambled. Bit loopy. Not to worry — I'm better now. Right as furniture polish!" He paused, scratching his head. "Nope. That's not the word I want. What word do I want?"

"Rain?" Buffy prompted.

The Doctor pointed at her. "Yes. Rain. Exactly — it was raining." He put an arm around her shoulders, pantomiming the scene in front of her. "Lightning flashing! Thunder shaking the ground! And the constant thud of pounding rain! Oh, and a gun. There was also a gun. I don't remember much else." He let go of Buffy and began to walk onwards. "But it'll come back to me! I know it will!"

Angel grabbed the Doctor by the coat and dragged him backwards. "Oh no, you don't!" He glanced at the sky. "It hasn't rained in weeks, Doctor. I don't know what you think you're talking about — but it's obvious that there's something seriously wrong with…"

"You," the Doctor snapped, yanking his coat out of Angel's hands and thrusting a finger in his face, "shut it. And you…" He pointed at Buffy. "...don't shut anything, because you're being extremely helpful."

Then he spun back around and ran off.

Buffy staked another silver lizard that was climbing up a nearby wall. Then tried to run after the Doctor — despite the crowds. "Wait! Where are you going?!"

"I have absolutely no idea!" the Doctor called back, as he disappeared into the crowd. "Marvelous, isn't it?"

* * *

They found him.

Eventually.

"You know that whole… brain damage thing he thought he had?" Angel checked, as they approached the Doctor. "I'm gonna go out on a limb, here, and say… he was right."

The Doctor was staring at a brick wall at the far end of an alleyway, as if it were the most utterly fascinating thing in the entire universe. He touched it. Smelled it. Licked it. Tried to look through it. Then, finally, he tried to take a bite out of the brickwork.

"Yeah, I'm starting to worry about him, too, actually," Buffy admitted. She stepped forwards, clearing her throat. "Uh… Doctor?" She gestured at the wall. "That's a wall."

The Doctor spat out dirt and brick residue. "Yep. I was just coming to that conclusion, myself." He rapped his knuckles against it. "Wall. Definitely a wall."

For a while, no one said anything.

"And…?" Buffy prompted.

"Hm?" The Doctor slipped on his brainy specs, moving so close to the wall that his nose pressed against it. "And what?"

"And… explainy-time!" Buffy snapped. "Come on! Make with the outer-spaceyness. If it's just a wall, why're you going all brainy-specs brick-muncher on it?"

The Doctor shrugged. "Well, thing is — I don't know." Then he stepped back and flipped his sonic screwdriver in his hand. "So let's find out!"

He pointed the sonic at the wall.

But before he could turn it on, the Doctor was grabbed from behind and dragged backwards by Willow, Giles, Cordelia, and Xander — who had somehow managed to sneak up on them all. They shoved him to the ground, yanked his hands behind his back, then tied his wrists and ankles with rope and shoved a cloth gag into his mouth.

"Buffy, are you all right?" Giles asked, as he finished securing the Doctor. He went up to her, clearly concerned. "Has he hurt you? Said anything to you?"

Buffy clenched her fists. She really wished she could grow up faster, sometimes — just so people would actually listen to her!

"I told you, Giles," Buffy insisted, "the Watchers' Council lied. The Doctor isn't evil. He's my friend!" She turned to the other Scoobies. "And you guys said you were okay with him! Remember? I made you cookies!"

"Yeah, we were," said Xander. "Until Oz disappeared."

"We've been doing research, Buffy," Willow put in. "The books were clear. And then we thought, and realized… people only started disappearing when _he_ arrived. And the disappearances only ever happen near him! Don't you get it?" Willow felt the Doctor struggling, and yanked the ropes around his wrists even tighter — until he gave a muffled yelp. "He's doing it, Buffy! It's all him!"

Giles placed his hands on her shoulders. "You are the Slayer, Buffy," he reminded her. "You have a sacred duty to defend the world. And you must. You are all that's left to fight off the forces of darkness."

Buffy frowned. She glanced over at the Doctor, but Angel stepped in and shot her a pointed look, one that warned her to back down.

The Doctor struggled, as the Scoobies dragged him away from the alley and back towards the school. Buffy hesitated, spinning back around and analyzing the wall that had so fascinated the Doctor.

There was a silver lizard crawling across it.

She staked it through the heart, then sighed, and headed off alongside Angel and Giles.


	8. Chapter 8

**Twelve years later — Oxford, 2011**

Alison was now the one pacing back and forth inside the cafe, feeling restless and worried and a bit panicked. There were even more silver lizards outside, now — and a small group had huddled right outside the door to the cafe, waiting for its occupants to emerge.

No weapons, not a great place to defend — but, like it or not, they were stuck here.

"Right — so," Alison said, spinning around and pointing at Seo. "Your mum knows what's going on. She probably knows where the Doctor is. But she won't tell us, because whatever she's doing is dangerous — and she wants to keep us safe."

Jenny's eyes were growing increasingly unfocused, as she began to drift into a trance.

"And when Buffy turned up on my doorstep, earlier today," Alison continued, dropping her hand, "she seemed to know all about these lizards, but thought the one we were after was some sort of scout — and we had to grab it before it reported back to all the others."

Seo just stared at Alison, without seeming to have heard a word. She still looked scared and withdrawn.

"And… and…" Alison threw her hands into the air. "And what's with you two? What, did the TARDIS decide to translate so that I only speak Swahili, now?"

Jenny didn't understand Alison's anger. "We can hear and understand you perfectly."

Alison gritted her teeth, struggling to hold back utter frustration. "Look, Seo's mum knows something — and she thinks Giles can help," said Alison. "To me, that says one thing. Something similar must have happened to Buffy back in Sunnydale, and now she's… oi!"

The last exclamation was shouted at Jenny.

Because Jenny was now opening the door, clearly in the midst of a trance, and walking outside. Three lizards scuttled inside the cafe, the moment the door opened.

Alison sprung forwards, grabbing Jenny by the arm and yanking her back inside. "No! Jenny, what are you doing?"

Jenny didn't answer. Her face looked blank as all the other zombies'.

Alison felt Jenny struggling to get outside, but Alison dug her heels in and wouldn't let her go. "No, Jenny — listen here! Jenny!" She clicked her fingers in front of Jenny's face. "Wake up! You can't just…!"

A scream tore through the air. Seo's scream.

Alison spun around — just in time to see Seo jump to her feet, grab up Alison's laptop, and thud it down onto the lizards in front of her… once, twice, three times… utterly panicked. Bits of the laptop flew off with every hit.

"No, Seo, don't…!" Alison cried, letting go of Jenny so she could save her laptop.

Seo managed to smash the last lizard by the time Alison wrestled the laptop away from her — but the laptop was pretty clearly as dead as the lizards.

The door to the cafe opened and shut, behind them, as Jenny left. Alison spun around. Swore. Then ran back to the door. "No, Jenny, wait…!"

But Jenny had already wandered into the crowd of zombies and out of sight. Seo, behind Alison, collapsed to the ground in the meantime, curling up into a ball and holding her head in her hands, as her whole body shook uncontrollably, and she hyperventilated strongly enough that Alison was afraid she might pass out.

Alison threaded her hands through her hair. Oh, God. So much for defending Seo and Jenny! She'd made a right mess of that one!

Then she calmed herself down. Refocused herself. And slammed the door shut before any more lizards could come in. She grabbed up her gun and shot the ones that already had. Yes, Jenny was a zombie now — Alison knew that. But who in Oxford wasn't?! That was normal.

Seo's breakdown wasn't. She knew something.

Giving a silent apology to Jenny, Alison sprinted over to Seo, kneeling down beside her and putting her hands on Seo's shoulders.

"Seo," Alison said, trying to stifle her friend's panic attack. "Please, whatever this is about, talk to me. Tell me what's going on. I can help."

Seo leapt to her feet and tried to dart away and make a run for it — but Alison leapt forwards and caught her. "No, Seo, wait!"

That was when Alison realized… Seo was too weak to get out of her grip. What was going on here? Why was Seo this weak?

"No, really," Alison demanded, "what happened to you three in the TARDIS, just before you wound up here? And where's the Doctor?"

Seo didn't answer. She still looked panicked.

"Right," Alison said, keeping hold of Seo with one hand as she flipped her mobile out with the other. "Fine! You're traumatized, but no worries." She selected a number, then waited as the phone dialed. "If this is something from your mum's past — I'll just ring Giles and ask _him_ for help."

Help with the monsters.

And with fixing Seo.


	9. Chapter 9

**Twelve years earlier — Sunnydale, 1999.**

"Okay, so it's… right hand rule," Buffy said, flipping past a vampire and staking him in the back. She adjusted her grip on her stake, so she could do the right hand rule around it. "Magnetic wire goes around like this, so my thumb points to the left. Which means that's the direction of the magnetic field."

She demonstrated by yanking her hand left, in the direction of the theoretical magnetic field of the problem — and jamming the stake into a second vampire's heart.

"Death by magnetism," Buffy commented, as the vamp dusted.

The Doctor bounced over to her. "That's it! Right hand rule! Brilliant! Absolutely…" He trailed off, as the cheer fell off his face, and he looked around himself, suddenly concerned. "Wait a tic. That's not right."

"What's not right?" Buffy readjust her grip on the stake, trying the right hand rule again, to see if she'd screwed it up. "I mean, I know I'm not all physics-geek Buffy, but… I like the hand-rule things." She flipped the stake in the air, and caught it. "They kind of go with my lifestyle."

The Doctor looked down at his hands and wrists, a look of intense concentration on his face. "It's almost like… a feeling. Like I should be restrained… or…"

The Doctor looked even more uneasy than usual. Buffy grimaced. She moved the stake to her left hand and tried the right hand rule stakeless, just to check.

A small, silver lizard scuttled out, in front of her — and Buffy lunged out and staked it with her left hand.

"So, uh… is there a left-hand rule?" Buffy asked the Doctor, trying to hide the lizard so he wouldn't notice she'd killed something.

The Doctor turned on her. "How long have I been here?"

Buffy blinked. "Huh?"

The Doctor grabbed her by the shoulders. "How long?"

"Three days," Buffy said. "One math study day and two physics study days." She shot him a grin. "I got back my math test. Guess what? Solid A."

The Doctor didn't seem to have heard her. "So this is day 3, then? Yes?" He ran a hand through his hair, pacing. "Right. Course it is. Day 3."

Buffy stepped forward to say something, then stopped. She looked a little confused. Reconsidered, then fidgeted in place.

"Look, I know I'm not the most Willow of students," Buffy put in, "but… I mean, it's just…" She shuffled, a little awkwardly. "...not a lot of people think I'm all that smart. You know?" She gestured at the Doctor. "But when you help me out, you make me feel… like… smart. Einstein-kind-of-smart." She tucked some hair behind her ears. "That means a lot to me."

"Yes, well, plenty of geniuses were rubbish at school," the Doctor muttered, taking out his sonic screwdriver and buzzing it through the air. "Michael Faraday, Isaac Newton… me, of course…" He checked the readings, hit it against the palm of his hand, then buzzed the air again. "But that's neither here nor there. Important thing is — people are still disappearing, and we've forgotten, yet again, that we should be looking for them. Remember?"

Buffy blinked. Blinked again. Then her eyes lit up. "Yes! The disappearing people!" She looked around herself, confused. "Wait, why are we here, discussing the right hand rule, when we should be out looking for the disappearing people?"

"My thoughts exactly," the Doctor agreed. He spun around, examining the graveyard. "Right! Here's the thing: I've been in this sort of situation, before. Reality changing. Minds altering. Narrative, paradoxes, all that. Only problem is, this doesn't feel the same." He smacked his lips. "Air doesn't have the right taste to it."

Buffy tried smacking her own lips, but didn't get any weird air-taste.

"Despite all that, one thing is clear," the Doctor continued. "Whoever is in charge of all this seems terribly concerned about your academic success in physics and maths."

Buffy blinked. "Huh?"

"No, no — except, it's more than that," the Doctor said, thinking aloud. He scratched his head. "Every time I'm in danger, I find myself suddenly out of it, again — and, instead, I'm back with you, teaching you physics or maths. Every time I try to investigate the disappearances, I'm stopped — and wind up teaching you physics or maths." He spun back to her. "And I've got two theories about why that is."

Buffy squashed a silver lizard underfoot, then jumped up to sit on a tombstone. "Okay. Theory me."

The Doctor raised up a finger. "One!" Gestured around himself. "We've somehow wound up trapped in some sort of educational computer game — and the people who disappear have literally been glitched out of the game."

Buffy nodded, slowly. "Okay… I don't get how, but… maybe a spell or something?"

The Doctor held up two fingers. "Two," he said. "The first night I was here, you said your mum wanted you to do better in school. She might — just might — have used the w-word around a vengeance demon, causing the two of us to be stuck in a sort of meta-universe in which all we can do is study."

"What's a vengeance demon?" Buffy asked.

"Long story; I'll explain later," the Doctor dismissed. He raised up three fingers at her. "And three—!"

"I thought you said you only had two," Buffy insisted. "When did three show up?"

The Doctor looked between her and the fingers, a little sheepishly. "It… well, it sort of… it's a bit…" the Doctor shook out his hand, then thrust three fingers at her. "Three!" he said, again, with pointed emphasis. "There's some creature out there who hasn't properly manifested in our reality — but is about to. It's gobbling people up in order to gain power and enter into this world. And it wants me to teach you physics because it's hoping I'll drop hints about one of the parts of physics that it might find terribly interesting."

"Like… what? Right-hand rule? Newton things?" Buffy asked. "Gravity stuff? Or are we talking an atom-quark-gluon demon?"

The Doctor quirked an eyebrow at her. "I was thinking more along the lines of… well… time travel. How the Hellmouth works. How all your so-called 'magic spells' actually work." He shrugged. "Take your pick."

Buffy cringed. "Okay, that actually does sound kind of likely."

The Doctor grabbed her by the hand and pulled her off the tombstone. "I think so, too!" he decided. "But whatever the answer, it's clear where we'll find it! That terribly ordinary brick wall I was looking at, last night."

* * *

It was still just a brick wall.

There was absolutely nothing special about it, whatsoever.

"Why is this thing so interesting to you?" Buffy asked him, as he studied it carefully.

The Doctor wrinkled his nose, thinking. "Not sure." He pat the wall down with his hands. "Just have the oddest feeling I've seen it before. In a rainstorm."

He yanked out the sonic and buzzed it at the wall.

The ground shook around them, as the wall exploded into a purple-blue haze, its brickwork growing fainter and fainter by the second. The Doctor kept pressing down the sonic, undeterred by the shaking of the ground or the whining scream of buildings ripping themselves apart around him.

"Doctor, stop it!" Buffy shouted, yanking him back. "Stop it, now!"

He squirmed out of her hands and popped back to his feet, still buzzing the sonic at the wall. "Oh, no," he said. "No, no, no, no, no! This is part of it. Has to be part of it. Everyone and everything keeps trying to stop me, but that just means I'm getting close! There's something about this wall that someone's trying desperately to hide!"

That was when black stuff shot out of the wall and splattered across the world. People all around them began screaming, running around in a panic. Then the black stuff spurted out of the wall again, and suddenly, people began to vanish — rapidly.

Entire crowds disappeared. Almost the whole Sunnydale downtown vanished! The buildings screamed even louder as they cracked and split and crumbled.

Buffy leapt on the Doctor's back, yanking the sonic out of his hand and flinging it away. The ground stopped shaking, the buildings stopped screaming, the black stuff stopped splattering, and the wall turned back into a wall, once more.

"What was that?!" shouted Xander's voice, as he and the other Scoobies appeared at the far end of the alleyway. "What the hell did he do?"

Buffy didn't answer.

Neither did the Doctor. Well, how could he? He had to admit, he was well and truly stumped over this one.


	10. Chapter 10

**Twelve years later — Oxford, 2011**

Alison hung up, after failing to get through to Giles for a third time.

"Right, then," Alison schooled herself. "All up to you, Alison. So… first, get through to Seo. Next, find Seo's mum and father. Third, work out what these lizards are and what they have to do with the zombification. And fourth..."

Alison trailed off, staring out of the windows of the cafe. True, Oxford was huge, and she didn't expect to know everyone here. But… she was right by her college, so she'd expect that she'd know at least _someone_ zombying about on the pavement nearby…

Maybe one of her tutors, or one of her friends, or one of the shopkeeps she kept running into, whenever she went in to buy books or groceries or all the rest of it.

But she knew _no one_.

"Seo," Alison said, a little more urgently. She had to snap Seo out of this, somehow! "Seo, please, listen to me. It's me, Alison. You're all right, now. You're on Earth. Can you hear me?"

Seo didn't seem to. She was shaking even more than before.

Finally, Alison just broke down in utter frustration. "Oi!" she shouted, getting right in Seo's face. "Earth to Evil Hell Goddess! Come in, Key Girl! Rise and shine!" She snapped her fingers in front of Seo's face. "Wake up! Wake up! Free humans, all about you, ready and waiting for cyber-upgrade! No struggle, no fight! Five-minute-cybermen!"

"Ooh!" Seo cried, a light coming into her eyes and a bounce back into her step. She clapped. "Cyberconversion! Brilliant!"

Alison sighed. Yep. 'Brilliant'. Sure.

It was only then that Seo seemed to notice Alison. She swooped her into a great big hug. "It's been forever! How are you? How's Oxford? Do you know what Gwen's up to, now that Torchwood's gone?"

Yes, it looked like Seo was back to normal.

That had done the trick.

"Is it just me," Alison asked, warily, "or is it a bit disturbing that it was the _cyberplanner_ that finally snapped you out of it?"

Seo spun back around. "Snapped me out of…?" She suddenly seemed to notice her surroundings. Raced out the front door of the cafe and started running about, from person to person, grabbing them up and analyzing them, before letting them go. "Comatose. Unaware. Trance, maybe? Not exactly the best upgrade candidates, at any rate. Awful for cybermen. We must survive, and all."

Alison ran after her. Odd thing was, the silver lizards were all leaving them alone, now. In fact, if anything, they were scuttling away from them.

"Seo, if you could stop cyberplannering for two seconds," Alison gritted through her teeth, "I need to know what's really going on here! You were on the verge of a nervous breakdown, a minute ago — and now, you're fine!"

Seo shot her a puzzled look. "Was I? Really? Interesting." She tapped her chin, thinking it through. "The cyberplanner in me must have instinctively squashed whichever emotions were behind the breakdown — and probably most of the memories that went along with it. Which is why I'm now sane and rational, but don't really remember much of anything." Her eyes lit up, and she raced after one of the zombies. "Ooh! Look! That kid's wearing mom-jeans!"

Brilliant. From cyberplanner to fashion critic. Alison ran after her, irritated. "Seo, you told me the Doctor was gone — just… gone. Then your mum seemed to know exactly what was going on, and she freaked out and ran off. And now, you're…"

Seo spun back around — her eyes sparkling. "Wait!" she cried, running forwards. "I _do_ remember. I was on the TARDIS, reading some rubbish book about this bloke who lives on one of the moons of Jupiter and who gets into all sorts of love triangles, squares, hexagons…"

Alison coughed, pointedly.

"...and then the TARDIS went all funny," Seo continued. "Father started shouting! He was very cross with Jenny, for some reason. Absolutely livid! And the next thing I knew, I was…"

Seo stopped.

Something suddenly occurred to her. She looked at Alison, strangely.

"Hang about," said Seo. "Did you say Mom was _here_?"

Alison shrugged. "Showed up on my doorstep. Asked me to grab some weapons and help her track down a silver alien lizard. Normal enough."

"And this is… what? 2008?" Seo guessed.

"2011," Alison corrected.

Seo's eyes went wide. She spun on her heels and began sprinting, again.

"No, no, no, no, no!" Seo muttered, her eyes scanning the street. "This isn't right. Not at all! None of this makes sense!"

Yeah. That much, Alison already got.

"I figure your mum encountered these silver lizard things back when she was living on the mouth of Hell," Alison proposed, as she ran after Seo. "One of the adventures she and the Doctor had together. She remembered what happened to her, all those years ago, and is acting on that information, now, to…"

Seo grabbed Alison by the hand, practically dragging her down the pavement, behind, as she sped up. "Alison, listen to me," Seo said, very seriously, "because what I'm about to tell you isn't going to make much sense — but I swear to you, it's true. Mom isn't in the UK, right now. She's in San Francisco."

Alison felt her head spin. "What?" She shook it. "No. No, I remember! Your mum said she'd taken the bus here, and then she..."

"After Torchwood blew up, Mom was in Hell for at least a year," Seo cut in. "When she got back, she rented a flat in LA for a bit — you know, near Angel. Then she decided she hated LA, and got an offer to do some work for the San Francisco branch of UNIT. That's where she's living, now." Seo's eyes looked even more worried. "And I know she's not in the UK, because they've still got her on a terrorist watch list. Giles has been working on it."

Oh.

"You're really blowing the super-intelligent-alien thing, Seo," Alison commented. "You're supposed to be explaining to me how this all makes sense — not telling me more ways in which it doesn't!"

Seo gestured at the people around them. "And these people!" she said, her eyes darting between them. "Why do they all look so familiar? Like I've seen them in some… movie, or… something!"

Alison sighed. Yep. Way to make this all make sense, Seo!

Seo yanked Alison after her, as she zipped round a corner. Then, abruptly, she slowed. Then stopped.

Alison almost ran right into her back.

"Oh," said Seo, staring. She snuck forwards, analyzing the zombified figure ahead of her, with curious eyes. "That's why they're so familiar. No wonder Mom knew what was going on."

Alison didn't recognize the figure, at all. A young man, with extremely gelled hair and an eyebrow piercing. "Sorry, who's…?"

"Willow's ex-boyfriend — and one of Mom's Scoobies, way back when," said Seo, looking back at Alison. "He calls himself Oz."


	11. Chapter 11

**Twelve years earlier — Sunnydale, 1999**

"It wasn't his fault!" Buffy shouted. "He's not evil! He was just trying to help!"

The Doctor was locked up in the book cage at the Sunnydale high school library. Blimey! With all the times they locked him up, here, he might as well move in a settee and a telly and change his forwarding address!

"This is your destiny, Buffy," Giles reminded her. "It is your sacred duty to…!"

Buffy, in a fit of rage, yanked a bunch of Giles' books off the bookcases and threw them onto the floor.

Giles stared at her in absolute horror. The insult to his books seemed to sting him more than any physical injury could.

"The Doctor's my _friend_ , Giles," Buffy snapped. "I like him."

Giles sighed, and leaned down to pick up his fallen books. "Yes, but…"

"And I know you don't care," Buffy ranted. She threw up her arms in the air. "I know that you're all with the 'bewitched' and 'magic voice' and 'influence of evil' thing — but he isn't…!"

"Oh, my God," Cordelia said, threading her hands through her hair. "Will someone please shut her up?"

Xander stepped forwards. "Look, Buff — we're just trying to do right by you. But your mom thinks…"

Buffy cut Xander off by shooting him a glare that could petrify at 20 paces.

"I'll admit — I've looked into the matter," Giles said, carefully dusting off the outside of his books, before sliding each back onto the shelf, "and the evidence does seem to confirm that the Doctor isn't evil." He slid the final book into place. "But that doesn't mean he isn't dangerous. You know—"

Right. This was getting them nowhere.

"Sorry to interrupt this little tête-à-tête," the Doctor interrupted, from inside the cage. "But… is no one going to ask _why_ that completely ordinary wall reacted like that?" He scratched the back of his neck. "Because, thing is, if you scan that wall instead of ripping it open — the sonic tells you there is absolutely nothing special about it, whatsoever."

Xander turned on him. "You said you were brain damaged, right? So maybe you should just let us non-brain-damaged people deal with this — and stop screwing with the world!"

The Doctor frowned. "Ah," he said. "Yes. Right. That." He rubbed his head. "Thing is… I sort of feel like I've been getting significantly better, over the past few days. And at a surprising rate of recovery, too. Which is a bit odd, don't you think?"

"So, what? You're saying someone's disappearing people and feeding their mental energy to you, to make your brain better?" Xander demanded. "Is that it?"

The Doctor scratched his head. "That… is a somewhat terrifying, but very real possibility." He grimaced. "Would certainly explain the rapid recovery." He ran a hand down his face, thinking it all through. "Blimey."

Giles grabbed Buffy by the shoulders and spun her back around to face him.

"You saw what he did, tonight," Giles reminded Buffy. "How many people died because of his recklessness? You can't treat him like he's simply another of your friends." He pointed. "That man is dangerous."

"Yes, yes, possibly," the Doctor admitted, regaining his determination. "But, tell you what? If this is because of me — I _will_ stop it." He scanned his eyes across the room. "And then I'll get back Buffy's wolf friend, and I'll…!"

The Doctor trailed off. His eyes grew sad.

"Oh, dear," the Doctor said, eyes landing on Cordelia and Xander — but not Willow. Just Willow's book, hovering in midair. "Down one more."

Buffy followed his gaze and gasped, horrified.

"That doesn't matter," said Giles, pointedly, grabbing the book out of the air and putting it away on the shelf. "None of them matter."

The Doctor quirked an eyebrow. "Sorry?"

Buffy stared at Giles. "Uh… Giles?"

Xander seemed not to notice. He kept his eyes leveled at the Doctor. "You're to blame for this, aren't you, Doctor? Willow's gone because of _you_!" He stormed over, shaking with rage. "You've got some nerve, letting…!"

"Ignore the missing people, Xander," Giles said, pulling Xander away. "Willow does not matter. Neither does anyone else. This is all simply distracting us from our purpose."

The Doctor scratched his head. "Sure you're feeling all right, Rupert Giles?" He stepped closer to the front of the cage, poking his fingers through the meshing. "Haven't been hanging 'round some big bulgy alien with a bright orange proboscis, recently? Or swallowing any substances that are sort of a pinkish purple with…?"

"You!" Giles cut in, harshly, turning on the Doctor. "You claim to be Buffy's friend. You claim to want to help her." He flung a finger back to point at Buffy. "But can you understand what she's been through? Can you fathom how difficult this is for her? The Slayer. The one girl in all the world! She has a mission and a destiny, and she _must_ not stray from that path!"

Buffy noticed another lizard out of the corner of her eye and staked it.

"Right…" The Doctor scratched the back of his neck. "Just to clarify: what, exactly, is this 'difficult' thing that you expect Buffy to do for you?"

Buffy stepped towards Giles. "Giles, seriously, what's with the not-caringness?"

"There's nothing wrong with me, Buffy; I'm perfectly fine," Giles dismissed. He kept his eyes leveled at the Doctor. "You've done enough harm already, Doctor. So stop. Now."

Xander put his hands on his hips. "Yeah! Buffy knows better than to listen to you." He paused, then walked over to Buffy, a little sheepishly. "You… uh… _do_ know better than to listen to him, right? Just… don't want to ruin my street cred, here."

Buffy stared at everyone around her, in the room. "I have absolutely no idea what you guys are talking about."

"That makes two of us," the Doctor agreed.

Giles turned around, his anger falling away. "Buffy," he said with a sigh, approaching her, "I know how difficult this is, but you must go through with it. Everyone, everywhere, will die — and you are the only one who can stop it."

The Doctor leaned against the side of the cage. "Everyone, everywhere, will die? New one on me. Just who did manage to brainwash you, exactly — and what do they want? The Earth? The universe?" He gave a cheeky smile. "Because whatever it is, Buffy'll never go through with it."

Giles, in a burst of fury, turned on the Doctor. "You bloody alien!" he shouted. "Is that all you can think of — some mystery to solve or some masterplot to unravel? Is it really all escape plans and prison breaks and alien brain parasites and scientific rubbish, to you?!" He pointed his finger in the Doctor's face. "If you care, at all, for Buffy — you will cease this at once and…!"

Giles trailed off, suddenly looking a bit guilty.

"...and, just, cooperate, yes?" Giles cleared his throat, a little awkwardly. "Sorry, I'm afraid I rather lost my temper there, for a moment." He stepped back to the library desk, reached beneath it, and pulled out a tin of cookies. "Please… help yourself." He offered the Doctor one of the cookies from the tin, poking it through the wire meshing. "If there's anything we can do to make you feel more comfortable…"

The Doctor didn't take the cookie. Just looked between them all, utterly baffled.

"This is all mad," the Doctor muttered, running a hand through his hair. Then, louder: "Look, will one of you lot please tell me what, precisely, is going on here?" Waved at Giles. "Or are you just going to continue your vacillation between angry yelling and nicely offering me tea and scones?"

Cordelia ran into Giles' office. "Oh! I can do tea!" She emerged from the office with a teapot. "See?" Then looked inside it and frowned. "Uh… anyone actually know how to make tea?"

"Maybe _I'm_ the one going mad," the Doctor muttered, dropping his head into his hands. "Is that it? Am I just sitting about on a street corner somewhere, drooling while ranting about Hellmouths and odd brick walls and all that?"

Buffy grabbed the keys to the cage off the desk. "If you're crazy, Doctor, then so am I." Marched to the door of the book cage and unlocked it. "So screw what these guys say." Threw open the door. "I'm getting you out of here."

The Doctor beamed. "Oh, I knew there was a reason I liked you, Buffy Summers." He ran over and hugged her. "Brilliant! Absolutely brilliant — that's what you are!"

Giles was looking angry enough to throttle the Doctor with his bare hands.

"And now, I think it might be best," the Doctor decided, grabbing Buffy by the hand and tugging her behind him, "if we ran!"

The Doctor and Buffy sprinted out of the library.

"Okay, it's… demonic possession," Buffy guessed, as they raced down the halls. "Like, a mass possession of tons of different people. Except you're all Time Lordy, so your brain works differently — which is why the mass possession is making your brain stronger instead of weaker. And Giles is trying to…"

Movement, to Buffy's left. A hand darted out and grabbed her sleeve.

Buffy spun around, yanked the person whose hand it was up by the shirt, and slammed them against the wall. Then Buffy blinked, as she realized who she'd actually grabbed.

"Oh, my God!" Buffy shouted, dropping the person. "Did you follow me? Are you spying on me?"

The person shuffled, awkwardly. "I just noticed the TARDIS was in Sunnydale, and… you know… wanted to see the Doctor and stuff." She grinned at the Doctor, and waved, excitedly. "So… hi!"

The Doctor stared at her.

He gave her a small, puzzled wave back.

He knew who this person was. This cheery little girl with a spark of attitude, her blue eyes passionate and her brown hair neatly combed.

It was Dawn Summers.

"Does Mom even know you're out here, Dawn?" Buffy demanded. She grabbed her sister by the arm and tried to drag her off. "No, actually, don't answer. I know she doesn't. And that means you're going right back home, before…!"

"Before Mom finds out that you're not really 'studying' — you're just hanging around your weird alien friend, again?" Dawn snapped, struggling against Buffy. "Come on, Buffy. Whatever's going on, I can help! Really!"

The Doctor ran a hand through his hair. "But that's… she can't be… not in 1999! It's impossible! It's… it's…" He shook his head, again. "I really _must_ be going mad."

That was when he heard the safety click off a gun, right behind him. He spun around, raising his hands above his head, and only then realized who, precisely, was standing there — pointing a gun at his head.

Buffy turned, too. Her jaw dropped. "Mom?!"


	12. Chapter 12

**Twelve years later — Oxford, 2011**

"Hello, Oz!" Seo cried, chirpily, her hands behind her back, bouncing on her feet. "Can you hear me?"

Oz didn't respond. He just kept staring straight ahead, blankly.

"Yoo-hoo!" Seo said. She waved in front of him, snapped her fingers, did some jumping jacks. "Oz! Come on, I know it's you. Easy to spot — the one person who'd make an absolutely rubbish cyberman." She grinned at him. "You remember me, right? We met during that thing with Father and Jenny and Riley Finn. Can't have been that long ago."

Still, nothing.

Alison analyzed him, carefully. "Who is this? And… why would he make a bad cyberman?" She cringed. "Or do I not want to ask?"

Seo glanced over her shoulder. "What? Oh, that! Well, he's a werewolf. Not good cyberman material." She leaned her head to the side. "Unless I could make a cyber-werewolf. I wonder…"

Alison cleared her throat, pointedly.

Seo blinked, and snapped back to herself, as she noticed Oz slumping in place. She reached out, trying to prop him back up. "You know, it's funny," she said, "but he looks quite a bit younger than the last time I saw him."

Another figure suddenly appeared before them. This one also looked young, like a teenager, her hair red and her eyes vacant. And — oddest thing, yet — Alison _knew_ her!

The zombie almost fell over.

Alison raced out and caught her.

"But she's… but it can't be!" Alison cried. She managed to get the girl steady on her feet — although still zombified. "It's the magic one from the Slayer Institute! Willow… something!"

Seo left Oz and rushed over to Willow.

"Willow," Seo breathed. She felt for a pulse. Looked into her pupils. Tried to work out anything that could be causing the trance. "No, no, no. This can't be…!"

Seo froze, for a second. Her hands were shaking.

She stepped back.

"This is wrong," Seo said. She looked around herself, and shuddered. "All wrong. This is her when she's just a kid! Everything with the First, the Toclafane, the Demon Civil War — none of it's happened to her, yet!"

"So there's something wrong with time?" Alison asked.

Seo spun around. "Time? Not just time! Something's wrong with all of _causality_ , Alison! Don't you see?" She pointed at Willow. "Without Willow, Mom would be dead! Several times over! If it weren't for Willow, _you_ would be dead! But you're not, so…!"

Seo stopped, in mid-sentence. Froze. "Unless…" Her entire expression grew panicked, as the possibility crashed on top of her.

"What?" Alison asked. "What is it?"

"Unless… we didn't land the TARDIS _in Oxford_ ," Seo said, "but in Sunnydale, back in Mom's past — and time hasn't had a chance to catch up yet."

Alison grimaced. She suddenly felt very mortal. "You mean… I'm going to die?"

Seo grabbed Alison by the hand, tightly. "No. But we have to find Mom — and soon." She ran back to the main street, where more of those lizards were skittering around. "You're right — everything happening in Oxford right now is linked to Mom's childhood. She's the key to all of this. And I'm betting that whatever happened in Mom's past, in Sunnydale, will explain precisely what happened to Father."

Made sense to Alison. Well, sort of.

"I don't know where your mum went, though," Alison insisted. "She said something about the Doctor, and that she couldn't keep control, anymore. And then she was off!"

Seo's eyes were fixed on those silver lizards — still scuttling, en masse, to some unknown destination. "Follow the trouble," she muttered, "and you'll find my parents."

She yanked Alison after her, as she sprinted down the street, following the lizards. If she was right — and there was always a chance that she wasn't — there was some sort of barrier or doorway or time corridor, linking this place to Sunnydale.

And if they didn't find it soon… Willow's extraction from history would catch up with them… and Alison would be dead.


	13. Chapter 13

Author's Note: Love this.

Enjoy!

* * *

 **Twelve years earlier — Sunnydale, 1999**

"Mom!" Buffy cried, horrified, looking between the gun in Joyce's hands and the Doctor. "You can't…!"

The Doctor shushed Buffy.

"Call it a hunch," the Doctor whispered, leaning down to Buffy, "but… I don't think that's really Joyce." The Doctor straightened, and he looked Joyce right in the eye. "Come to think of it," he said, in a louder voice, "I don't think any of this is really what it seems. Is it?"

Tears appeared in Joyce's eyes. Her hands shook around the gun.

"Doctor, please," Joyce said. "I'm begging you. Stop trying to figure this all out. Stop trying to see the outside of the cage. Please! Just go back into the library. Open up a book. And…" she looked over at Buffy. "...teach her."

A spark of curiosity appeared on the Doctor's face.

Buffy stomped forwards. "Mom, listen to me! You can't…!"

Joyce ignored her. Her eyes didn't stray from the Doctor. "There is no mystery to solve," Joyce begged him, struggling not to cry. "No prison to break out of. No big bad. Just one person and her stupid inability to do what has to be done." Her voice trembled. "So stop trying to escape. Stop sonicing that spot on the wall. Please — you're killing me."

The Doctor looked between 12-year-old Dawn, and Joyce Summers. His mouth formed an 'o', as he stepped back, suddenly understanding.

"Mom, there are people disappearing and stuff," Buffy insisted. "The Doctor's gonna help us find them, again. Don't you get it? He's not evil!"

A tear trickled down Joyce's cheek.

"Yes, they are disappearing," the Doctor said, lowering his hands, slowly. "But… I don't think they were ever real. They were only here as a shield — to protect me."

Joyce still didn't shoot.

"Oh, Buffy Anne Summers," the Doctor said to Joyce, finally working out who she really was. "I'm sorry. I am so, so sorry."

Joyce took a shaky breath. "Just… go back. Accept this. Stop trying to fight—"

"Where am I, really?" the Doctor asked. He looked about himself. "Not where's my mind, I mean — because, clearly, my mind's in here. But — the rest of me. Where am I?"

Joyce said nothing.

A second tear rolled down her cheeks.

"Buffy," the Doctor said to Joyce. "You have to…"

Something inside of Joyce snapped. "Don't you understand?!" she shouted. "The monster wants the information inside your mind, Doctor! I can already feel the monster starting to break in here, in order to get at you. If I tell you anything — you'll remember, and the monster will find out, and _everyone_ will die."

The Doctor looked between Buffy and Joyce. He gave a slow nod. "Teach her. I see." He gestured at his body — with the spiky brown hair and pinstripe suit. "This isn't even the right me, is it? Not the current incarnation. You shaped this avatar based on your memory of me — a pleasant memory from your childhood."

"Stop," Joyce begged him. "Please. Stop."

18-year-old Buffy, noticing another silver lizard crawling on the wall, staked it. Then turned back to the Doctor, looking thoroughly confused. "What is she talking about? Doctor, what's wrong with my mom?"

"Your mum is… very brave," the Doctor told the 18-year-old Buffy beside him. He squeezed her hand a little tighter. "Thoughtful, brave, clever, and unbelievably kind." He let go and stepped forwards, automatically reaching up to adjust a bow-tie… before he realized he didn't have one. "She must have found me when I was about to die. At great risk to herself, she used her own mind to help heal mine. And, knowing I required a closed environment for my mind to recover properly, she placed me in Sunnydale — the one locked room where I could run about and feel like I was free."

Joyce didn't answer.

She never lowered the gun.

"But you can't hold me here forever," the Doctor told her. His voice lowered. "You know this is killing you. You need to let me out."

"If I let you out, everybody dies," Joyce said. She looked around herself, as the lights in the school flickered. "I thought I'd fixed everything. I thought I'd saved the others. I thought I could save you, too."

The lights flickered, again.

"But it's too much," Joyce insisted. "I can't…!" She lowered the gun, a little. "The monster found out what happened. Tracked down the others. Oxford, 2011. I was trying to protect them, but then you…"

The Doctor looked around himself, as the landscape suddenly changed. He could see himself running through the rain, buzzing his sonic screwdriver around, trying to feel out the walls of his prison.

"I weakened your mental defenses," the Doctor muttered. "And then, when you stopped me, I came back a second time — and weakened them, again."

The school and its hallway popped back into existence around them. The lights kept flickering.

The Doctor turned back to Joyce. "You have to tell me what's really going on," he said. "Tell me everything. We can work this out together — I promise."

"You don't know how much I want to," Joyce insisted. She still had the gun trained on him. "But I've got a duty to something larger than myself. So I have no choice."

"You're killing yourself," the Doctor told her.

Joyce's hands kept shaking around the gun. "I know," she said. "That's the easy part."

The Doctor frowned.

"The hard part is who else I have to kill," said Joyce. She took a long, deep breath. "I'm so sorry, Doctor."

She pulled the trigger.

* * *

 **Several days earlier (again)**

The Doctor wasn't sure how he'd gotten to Sunnydale. Something was wrong, here — he could feel it, like gooseflesh dotting his skin. But he couldn't work out what. He just kept feeling like he'd skipped back a few days — but he had no memory of doing so.

He placed his hands in his tan trench coat, looking at the blond girl with the stake as she ran through the graveyard, flipping and ducking and dodging the monsters that attempted to kill her.

She dusted the last vampire, and looked up. She noticed the Doctor.

Joy and brilliant happiness washed across her face.

"Okay, I know this is going to sound like I'm begging," Buffy said, running over to him, "but the thing is — you're really smart, and I've got a math test tomorrow." She raised up her math textbook. "So… um… I mean…"

Two silver lizards scuttled across the ground, and Buffy squashed one with her foot and slammed down the math textbook on top of the other. Then she tried to hide the corpses from the Doctor.

"Silver lizards," the Doctor muttered. "Silver lizards. Why does that seem familiar?"

Buffy tried to wipe the lizard blood off the cover of her textbook. "I mean, I've been doing all the homework and whatever, but… the steps keep getting jumbled in my head. And when Willow tried to help, I just got more confused."

The Doctor glanced back at his TARDIS. "You know," he muttered, scratching the back of his neck, "I have this horrible feeling that, the longer I stay here, the more I'm killing someone I care about very deeply."

Buffy lowered her textbook. "Huh?"

He sighed. Then he turned on his heels and headed back to the TARDIS. "No, it's no good. I have to go."

The moment he inserted the key into the lock, though, the ship vanished, in front of him. The Doctor stared, jaw dropping. He turned back to Buffy, who was just giving him a hurt puppy-dog look.

"Please?" Buffy begged him. "Pretty please?" Buffy extended the book to him. "Help me?"

The Doctor looked between her and the book, still feeling uneasy about this. Then he sighed. Oh, who was he kidding? He couldn't say no to someone asking for help!

(Besides, a bit of teaching might clear up this slight fuzziness still inside his head. Get the neurons working, again. It usually did.)

The Doctor gave a grin and accepted the book.


	14. Chapter 14

Author's Note: And now, we get a little more information about what's going on...

By the way, I couldn't explain it before, but I will now. I began writing this story while rewriting Paradox (I'm sure you'll notice some similarities). I was rewatching Buffy episodes and enjoyed the way they combined the benign and the supernatural... and had this idea that it would be beautiful to have the Doctor and Buffy bond over math-tutoring. Meanwhile, I was wondering if I should actually rewrite Paradox with a totally different plot, or if I should create a brand new story that was separate. After all, I was thinking, if the plot of the new Paradox is so different from the old one, maybe it was just a new story!

So one day, I sat down, opened a new document, and started writing. My goal was to write the plot of New Paradox as its own story, and combine it with my math tutor idea. However, in the end... uh... well, I guess you can see the results. I got a completely different plot, yet again.

To summarize: I've now sat down to write Paradox 3 different times, and have (as a consequence) wound up with 3 very different plots.

I'm not sure what that says about me.

Anyways, enjoy!

* * *

 **Oxford, 2011**

As far as Alison could gather from what Seo was continuing to explain to her while running — every single one of the zombies wandering about, here, were from Sunnydale.

"So where's everyone who's supposed to be in Oxford?" Alison asked, confused. "Why aren't they here?"

Seo scratched her head, like she was trying to scratch an itch inside her brain. "There's a sort of psychic signal, I think, telling people to stay home. Everyone else must have picked up on it."

Alison didn't know why she hadn't, but she figured that wasn't important. "Right. Fine. So why are people from Sunnydale being transported here — but as zombies?"

"No idea," Seo said, as she kept running. A gleam appeared in her eyes — as it always did, when she realized something was a mystery. "Let's find out!"

But it was only as they approached a storm drain and realized the lizards were running down into the sewer… that Alison's mobile rang.

She looked at the display, then answered it, with a sigh of relief. "Giles!"

"Yes, quite sorry," came Giles' voice, over the phone. "I was rather in the middle of something — and found both you and Buffy had rang me, in the meantime. Is anything the matter?"

Alison glanced about herself. "Silver lizards, zombies wandering about, psychic signals scaring people off, and Seo and Jenny say the Doctor's simply vanished into thin air."

A pause, from Giles. "I… see." The ruffle of paper and books, on the other end. "Well, nothing springs to mind off the top of my head, but I'll see what I can find."

That was odd. Alison had thought that Giles would remember this from Sunnydale, way back when. Why wasn't he?

"No," Alison insisted. She shook her head. "No, no, no! You didn't hear me properly. Silver lizards! Zombies! Vanishing people!" She gripped the mobile a bit tighter. "Doesn't that sound familiar?"

Giles paused a moment, thinking. "No," he admitted. "Not really."

"But they're from Sunnydale!" Alison cried. She swung her arm out, spinning about and staring at the zombies around her. "Seo says every one of the zombies is some person transported here from a twelve-years-ago Sunnydale! And we found Willow — but she's just a kid. Not even in uni, yet!"

This time, there was a much longer pause from Giles. "That's… troubling." There was a sound, as if he were closing a book. "I think, perhaps, I should ring Buffy. Angel said she might be in a bit of trouble."

Angel?

Alison's eyes went wide. Course! Angel! Buffy had mentioned something about Angel. And Seo said that Buffy shouldn't be here, right now.

"But Buffy's here!" Alison insisted. "She turned up out of nowhere and asked me to help fight off some alien lizards, and then Seo and Jenny turned up, and Buffy just… ran off!"

"I'm sorry?" Giles asked. He sounded perplexed. "Buffy is… in Oxford? Really?"

"Yes, she…!" Alison started.

Seo raced in and yanked the phone out of Alison's hands.

Alison spun around and tried — unsuccessfully — to grab it back. "Oi!"

Seo pressed the phone to her ear. "It's temporal, I think," she said. "That's why you can't remember. Jenny, myself, and Father must have landed back in Mom's past, and done something to muck about with…"

She trailed off, as Giles cut in.

Her eyes grew horrified, as she listened to what Giles had to say.

"But… but I don't remember… sending…" Seo began.

Giles said something else.

And the phone tumbled out of Seo's hands.

Alison swooped in and caught it, before it hit the ground. Why did everyone in Seo's family seem determined to break her iPhones and laptops and such? It was driving her mad!

"Me, again," Alison said into the mobile. "What did you…?"

The sound of books being thudded into a bag. "Alison, I want you to find someplace easy to defend, and lock Seo and yourself in there until I arrive. Do you understand? And whatever you do, do _not_ let Seo run off to save her mum!"

"But…!" Alison said.

"I'll be there soon as I can," Giles insisted. "But this is horribly dangerous. Trust me, whatever you think you can do — you're wrong. And trying will only make things worse."

Then Giles hung up.

Alison turned on Seo, now more determined than ever to get some answers. "All right, Seo! What did Giles tell you?"

Seo swallowed, hard. Then planted a grin on her face, and grabbed Alison by the hand. "Come on! We have to find Mom and…!"

Alison dug in her heels. She'd been told by two different people, now, that she had to stop Seo from following Buffy. She was starting to get the idea that whole lizard thing was very different to what either of them had hypothesized.

"But Mom is…!" Seo started.

"Oi! You listen, here!" Alison snapped. She pointed towards her flat. "I've got a tutorial tomorrow. So either you tell me what's really going on, or this whole bloody alien invasion can get stuffed — because I'm going home to write a paper. Got that?"

Seo tugged her hand free from Alison's.

She hesitated. Then, finally, gave in.

"Giles told me that… three days ago," Seo said, quietly, "Angel received a hypercube message from me, intended for Mom." Seeing the blank look on Alison's face, Seo qualified, "A hypercube is a Time-Lordy way of sending messages through time."

Alison nodded, slowly.

"When Mom got the message, she told Angel that the Doctor was in very serious danger," said Seo, "that Jenny was probably already dead, and that I was running about, inside the TARDIS, frantically trying to hide — while barely fending off psychic attacks from something intent on ripping my mind to shreds. Mom said… I was opening up a temporal portal for her. And then she told Angel… what to do if she didn't come back."

Alison felt her head spin.

This wasn't at all what she'd expected. Not one little bit!

"But I don't remember doing any of that!" Seo insisted. She cradled her head in her hands, as if trying to force the memories back to her. "All I remember is — one moment, we were in the TARDIS, and the next…!"

Alison took a shaky breath, as she shoved her phone back into her pocket. She could remember that when Seo had first arrived, she'd been on the verge of a nervous breakdown — and it had taken the aggressive emotion-flattening of a cyberplanner to snap her out of it.

If something had gotten inside the TARDIS, some monster that could tear apart minds, and it had already gotten to the Doctor and Jenny, leaving Seo trapped and hiding and terrified, watching as everyone else was nearly killed around her, feeling as the monsters tried to do the same to her…

That might go a long way towards explaining the breakdown.

"Your mum rescued the Doctor, didn't she?" Alison guessed. "She defeated some big bad, but it had already hurt the Doctor very badly… badly enough that you thought he was gone for good. So your mum hid him here, in Oxford, 2011. Problem was, the big bad found him. So now, she's trying to fight it off."

Seo fixed Alison with a pointed stare — as if to say that, yes, obviously, and that was why they had to stop chatting and rescue the Doctor and Buffy, right now!

"Look, Giles said he was on his way," Alison insisted. "It's only an hour drive. We should wait until he…!"

"Mom could be dead in an hour!" Seo shouted. "Father, too!"

Alison didn't know what to say.

"Please, Alison," Seo begged her. "I need you to help me save my parents. Please!"


	15. Chapter 15

Author's Note: Hey, look at that! This scene has an ending, now. For the vast majority of its life, this scene ended with the line, "I should probably finish writing this scene at some point." So I just incorporated some of my very immense backstory into the scene and that finished it up for me.

FYI, to write this story, I did wind up with a file called, "This is Slay Study Told Forwards."

Enjoy!

* * *

 **Sunnydale**

Two monstrous-looking evil witches howled, as Buffy flipped herself into the middle of their Hellmouth-opening spell. She kicked at one, and punched the other. "Okay, um… carry the two…"

One of the witches unsheathed a scimitar, and the Doctor buzzed at it with his sonic screwdriver. The sword grew red-hot in her hands, and she screeched as she dropped it. Buffy punched the witch in the face.

"...810x," Buffy said, ducking a blow from a nearby lingering demon, as the witches turned and fled. Buffy grabbed the scimitar off the ground and lunged at the demon. "...no, wait. 810sin(x) = 5 +..."

The demon knocked her to the ground, but she rolled to her feet, scimitar still in hand.

The Doctor was about to warn her to please not kill the demon until she'd at least had the decency to talk to it — but something flashed through his mind, and the weight of it made him double over.

He could see a blurry image of a tall blond girl screaming, as something grabbed for her.

 _Jenny._

And then there was another snippet of a memory — a far shorter girl, blond but with wide brown eyes and freckles, shaking him, looking scared and begging him to get up, and he was struggling to get out words while he still could, struggling to tell her, "Run, Seo! Run for your life!"

The Doctor blinked, and came back to himself, realizing he had collapsed onto the basement floor right beside the Hellmouth — and Buffy was leaning over him, looking scared.

"Are you okay?" Buffy asked. "I thought… I mean, I knew I was bad at math, but I didn't think I screwed up solving it _that_ badly."

The Doctor sat up, looking about himself, and realized there was a whole swarm of dead silver lizards surrounding him. He picked one up, but it turned to dust in his hands.

"There's something very odd about all this," the Doctor muttered.

He put a hand up to his head. He kept getting more and more flashes of memory. They were fuzzy, indistinct, like he was remembering a dream. But it wasn't a dream. This was how the brain worked, when something had ripped it to shreds and it was attempting to heal itself — reality felt like a dream, and the only way you knew it wasn't was because you couldn't wake up.

 _"You shouldn't be here!" he cried — but he didn't know what language he was speaking, or if he was even speaking a language, at all._

 _An older version of Buffy was kneeling beside him, looking very worried. "I guess that's a 'what are you doing here' exclamation. Seo… sent me a hypercube. She brought me here." She looked back, and bit her lower lip. "The TARDIS is a wreck. It took me forever to find you." Her eyes filled with the horror of the memory of finding him. "For a moment, I thought you were already… that I was too late to…"_

 _He felt his eyes closing, as darkness encompassed him._

 _"Doctor?!"_

 _He felt someone shaking him, but kept drifting away._

 _"Doctor! Talk to me! Doctor!"_

The lights flickered, around them. Then, suddenly, they all shut off.

Next thing the Doctor knew, Giles was down in the basement, alongside Buffy, running a knife through yet another silver lizard. And — for no reason the Doctor could understand — Spike was at the other side of the basement, also trying to destroy lizards.

What was Spike doing here?

"Buffy, I understand your reluctance to do so, but this is your duty," Giles insisted. He pointed at the Doctor. "This cannot go on much longer. We are being overrun!"

Buffy said nothing.

She just kept staking lizards.

"One girl in all the world, to battle back evil," Giles informed her. "You are the Slayer, Buffy. It's time you acted like it."

The Doctor sat up, looking around himself. It was funny, but ever since he'd gotten here, he had the impression that Sunnydale was… strangely empty. He was expecting at least one of Buffy's Scoobies, here, but — no Xander, no Oz, no Willow, no Cordelia, no Tara. No one.

Giles sliced into another lizard that was skittering towards the Doctor.

"Buffy…" Giles urged.

Buffy rounded on him. "Just because he isn't human doesn't make him evil, Giles!" She pointed at the Doctor. "I'm not killing him. End of story!"

Giles took his glasses off his face, wiping his eyes. "Your mother and I have discussed this at some length, now," he said. "Sunnydale is overrun, and we're losing any defense we had against them. Worse, still, he's remembering. It's only a matter of time before he does something he cannot take back, and everyone dies."

The Doctor took out his sonic screwdriver, and buzzed it at the ground. Around him, the entire basement went dark, revealing that they were all in the middle of something that looked like a glass bubble, with hundreds of thousands of tiny lizards crawling across the outside.

Spike whacked the sonic out of the Doctor's hands.

In a second, the basement returned — along with Sunnydale and the Hellmouth.

"You're a bloody wanker, you know that?" Spike told the Doctor. He took a drag on a cigarette. "Think you're making things better for yourself, trying to tear this whole thing to pieces?" He waved the cigarette in the Doctor's face. "We nursed you back to health, you know — and this is how you repay us all! Wrecking the bloody place and not caring in the slightest!"

The Doctor stared at Buffy. He was starting to remember that, too, through the thick fog of a damaged mind. The Summers' household… Buffy with freshly baked pancakes or brownies or banana bread or whatever she'd cooked up for him that day… Joyce with medicine… all Buffy's friends dropping by to help…

But that didn't make sense. Didn't Buffy's friends all hate him, at this point in time?

"Perhaps I'm going mad," the Doctor said, hand on his head.

Giles glared at him. "No, Doctor. You're sane and well, now. Far too well. That's precisely the problem." He shook his head, and returned to staking lizards. "Now, if you've any sense at all — stop remembering and help us!"


	16. Chapter 16

Author's Note: My sister got a traumatic brain injury a few years ago. It was horrible. I was so scared for so long. This story is a little of a Hollywood version of that (in that it's way shorter than in real life and I cut out stuff that didn't work with the plot), but I still took things from the real-life experience.

In case you're wondering, my sister is fine. She recovered and is now back to being a scientific genius. The brain has remarkable powers of recovery.

Enjoy!

* * *

 **Oxford, 2011**

"You're enjoying this!" Alison accused, as they wandered about in the sewers, using Alison's iPhone for a torch.

Seo shook her head. "My parents are in danger! Of course I'm not…!"

"Oh, shove off!" Alison rolled her eyes, as she elbowed her in the side. She shone the torchlight in Seo's face. "I know that look on your face. Silver lizards. Complete amnesia. Sunnydale residents running about. You want to work out the mystery!"

Seo ventured a small smile. "Well, don't you?"

Alison had to admit, it sure beat reading up on Vikings — even if she did seem to wind up in a lot of sewers, when she did this sort of thing. She paused, frowning, as she heard a huge amount of scuttling down a side passage in the sewers. Alison gestured at Seo to follow her, and they went down the passage.

They stopped, as they arrived at a section of the sewers that was filled with water pipes and fios cables and gas pipes, but without an abundance of sewage. However, every single surface around them was covered with small silver lizards.

And one pillar was covered with more of them than any other.

No, not a pillar, Alison realized. It had the shape of… well, actually, it looked a bit like a police box — but the lizards clinging to every bit of its exterior made it look far lumpier and more misshapen than usual. The door was open, exposing an interior also strewn about with lizards. More and more lizards were attempting to enter it.

"The TARDIS!" Seo cried. She turned to Alison, redirecting the light from the iPhone so they could see it more clearly. "But how did it get here? And why are the doors open? And when did…?"

Seo stopped talking, and frowned.

She could have sworn there was something she was forgetting. Something important.

Seo yanked Alison after her, stepping right on top of the lizards, so she could run over to the TARDIS. The lizards began to scatter, slightly, as she approached — allowing her and Alison entry into the ship.

"Why do I get the feeling this isn't the wisest thing we've ever done?" Alison asked, as they stepped inside.

The TARDIS console room was cold, with only a faint trace of internal lighting. Yet, even so, Alison and Seo stared at the room around them — its panels busted, wiring and machine parts tumbling out of the floor and ceiling and walls. Its pulse seemed weak and strained, like something was trying to strangle the TARDIS to death.

Alison and Seo looked about themselves, at the world's creepiest ship.

Then Seo spotted something by the central console, and cried out, running to it.

"Mom!" Seo shouted, as she rounded the figure of Buffy, lying, face-up, on the floor, her eyes closed, a swarm of lizards perched on top of her — and a coronet of wires hooked up to her head, linking her with the TARDIS' central console.

Alison ran over, as well, but noticed a second swarm of lizards over something else on the floor, lying right beside Buffy. This swarm was so dense that there wasn't even a body discernable beneath it — not at first.

Alison shoved the phone in her pocket, then knelt down and scrambled to pull lizards off the body before her. She could guess who this was, even before she found his face.

And, of course, she was right.

"The Doctor," said Alison. "Beaten up, hurt, and bloody, but still alive." She glanced at the coronet contraption around his head. "And also hooked up to the TARDIS — just like Buffy."

Buffy gave a shudder, a look of pain spreading across her face.

The Doctor didn't move. He looked perfectly peaceful.

"Seo, tell me you remember something about all this," Alison insisted. "Anything!"

But Seo never had a chance to answer.

The TARDIS doors slammed shut, and a bunch of the lizards seemed to melt and pool into a liquid metal, not far off from them. The liquid bubbled, then burst upwards in the shape of a person.

No… two people.

"So, we were correct, after all," said one of the liquid silver things. "The Key's mind is curious."

"Give her a mystery to solve and people to save, and she'll trap herself," said the other liquid silver thing. It took a step forwards. "Our gateway to the multiverse."

Seo tried to back away — but was caught by someone standing behind her, grabbing her by the wrists and restraining her. Seo looked back and realized… it was Jenny.

There was still a dull, zombie-like look on Jenny's face.

It made Seo remember — like something from far, far away —

 _"You can't bring that in here!" Seo cried, looking at Jenny's new silver pet lizard, cradled in her arms. "Father said no pets."_

 _Jenny looked at her, very sternly. "Are you going to tell him?"_

 _Seo gave a small grin._

 _Of course she wouldn't!_

 _Jenny pet the lizard, fondly. "He's cute. I found him on Grawino, and just knew I had to take him with me." She held him out to Seo. "Pet his belly. He likes it!"_

Alison grabbed her tranq gun out of her rucksack, pointing it at the two silver liquid people. "Who are you?"

The silver liquid people took another step forwards. "We are the Amansafari. And you, silly little human, can do nothing against us."

They pointed at her gun, and Alison found herself swarmed by lizards, all crawling towards the gun and then… eating it away… until it was nothing.

Alison shook the lizards off of her, in alarm.

"When we found this vessel, we thought we were getting a feast," said the rightmost Amansafari. It gestured at Jenny and the Doctor. "Our sensors picked up: a Gallifreyan and a Time Lord. They'd touched so many lives — could reach so many people! What a banquet. We could scarcely believe our luck."

"People are like onions," said the leftmost Amansafari. "Everyone they meet, everywhere they go — is another layer. One you can peel away… and devour."

Seo remembered… like a flash of a memory in her mind…

 _"What have you done, Jenny?!" the Doctor shouted, slamming the door shut and sonicking it locked. The TARDIS gong was sounding, around them, and they could hear the sound of thousands of lizards scraping against the locked door._

 _"It was just a lizard!" Jenny insisted. "I thought…!"_

 _The Doctor pointed at the door. "Those are the Amansafari. They find everyone you've ever touched — or ever could touch, in any alternate — and devour them." He spun around, and ran further into the TARDIS. "And you've just let them onboard the most powerful time machine in the whole universe!"_

"I… remember," Seo whispered. She shuddered. "You took over the TARDIS. Tore apart the console room. Chased us through the corridors. You used the symbiotic link to infect Father's mind."

"The Time Lord tried to fight, so we tore his mind to shreds," one of the Amansafari laughed. "I felt him dying as we descended upon him. His pain was a beautiful thing to behold."

Seo felt herself breathing a little harder. It was all coming back to her, now. Everything.

 _Seo, on the walkway in the TARDIS powerhouse, looked at the creatures approaching her on both sides. She didn't know what had happened to Jenny or Father. She didn't know anything. All she knew was… this was the core of what powered the TARDIS._

 _And, in its presence, she felt an incredible sense of inner power._

 _The Key practically glowed in her veins, in this place._

 _"Get out of the ship," Seo commanded them all. She felt a powerful burst of energy explode out of her. "Get OUT!"_

"And you connected to the TARDIS' energy, to kick us out of its telepathic circuits," said the rightmost Amansafari. It crossed its arms, looking on at Seo, its eyes greedy and ravenous. "But, in doing so, you revealed who and what you truly are — Key."

The leftmost Amansafari licked its lips. "Your reach extends past the bounds of our universe. With you, we can feed on everyone who ever lived — in any universe — forever!"

Seo put her hand on her head. "I… remember…" She began to tremble. "You tried to do the same to me. You… you tried to tear me apart! I ran. Hid! I was so scared. I was…!"

The Amansafari laughed at her terror and her pain. She was their banquet, and they were planning to draw out their meal for the entire lifespan of the universe.

Alison looked between Seo and the other two. She frowned. "But… you're not eating her up," she pointed out. She gestured at Buffy and the Doctor. "Not even eating them, far as I can tell. They're hooked up to the TARDIS, and Seo says she banished you from the TARDIS' mind. Is that why? You can't get back in there?"

The two Amansafari scowled, fixing their eyes on Alison. "The Slayer proved… difficult," they admitted. "But now that we have the Key and you, little human, we will finally be able to break her."

Before Alison knew what was happening to her, she found herself grabbed and pulled away from Seo by the two Amansafari. She tried kicking and screaming and struggling, but it did no good.

Seo also struggled against Jenny — but was unable to break free.

"Portal," Seo realized. "Giles says I made… a portal. That, combined with whatever I did in the powerhouse — must have zapped most of my energy."

The Amansafari ignored her. They turned back to the central console.

"You listening, Slayer?!" they shouted. "We have your pupil, here — Alison Korjensky! If you don't come out here and defend her, she'll die."

At the far end of the console room, a woman emerged — almost shining, in the midst of the dark room. It was clear that whatever energy the TARDIS usually expended on light and power to travel through time — it was now spending it on whatever mental thing was happening with the Doctor and Buffy, and on creating this projection.

"I think you're forgetting," the Buffy projection said, stepping into the console room and crossing her arms, "that, when I first came onto this ship, I killed your entire first assault team." She paused, tilting her head to the side. "With a hatstand, come to think of it. I mean, seriously. A hatstand!"

More lizards melted into liquid, all turning themselves into more and more of the Amansafari. They glared at Buffy through murderous, drippy-silver eyes.

"I know you want the Doctor's mind," Buffy said. "But I'm not budging. So if you wanna tear it to pieces, again, you'll just have to eat me first." Buffy smacked herself on the forehead. "Oh! Wait! I forgot! I'm a Line Hopper — and, apparently, that makes me inedible to you."

The Amansafari gave a high-pitched screech that made Seo and Alison both double over and clutch their ears in pain.

Buffy didn't seem rattled by it.

"Was that supposed to scare me?" Buffy stalked towards them, her voice low, her eyes flashing. "I went up against the First Evil. I defeated a Hell Goddess. I destroyed Acathla, liberated his Hell Dimension. I even crushed an army of Daleks out of existence." She stopped, right in front of the Amansafari army, pointing her finger in their face. "I'm not a Slayer. I'm _the_ Slayer. And you don't scare me — not one tiny little bit."


	17. Chapter 17

**Sunnydale**

"Right! And then you can derive the equation… for…" The Doctor paused, in the middle of his happy ramble. He was seated in the library, right beside Buffy, a physics book open before them. He wasn't quite sure how he'd gotten there. "Odd." He looked about himself, trying to find anyone else nearby — but apart from Buffy, the library was empty. "Very odd."

A swarm of lizards raced across the floor, and Buffy jumped out of her seat, flipped through the air, and killed them all, one by one. Their blood spattered across the library's wooden floorboards.

"You know, I really do remember those," the Doctor said, getting up and staring at them. "They were in… the TARDIS…"

His head flashed with residual pain.

Buffy was by his side, in an instant. Her hand, resting on his shoulder, first eased the pain and then took it away, entirely — although how or why it did that was beyond his understanding.

"You know," the Doctor said, leaning against a nearby chair and feeling the wood beneath his fingertips, "this place looks real. It _feels_ real. It feels like Sunnydale — Hellmouth and all."

Buffy shot him a baffled look. "Okay, and now I'm all with the huhs."

"Well, let's face it — this isn't Sunnydale, is it?" the Doctor said. "But it feels real. Feels perfect! Well, unless you know it's not the real thing at all." He furrowed his brow. "And I do, because the more I think about it, the more I've realized that being here feels remarkably similar to linking myself into the Matrix on Gallifrey. Astonishingly similar."

"You said Gallifrey was gone," Buffy said to him, confused.

The Doctor paced the room, back and forth, like a tiger pacing his cage. "Well, not anymore — I'm brilliant, remember? Thank you, Clara! But I digress — nope! Can't be Gallifrey. So it must be the TARDIS helping to create all this. Someone's hooked me up to the TARDIS' matrix, and now they're trying to trap me inside a simulation of one of my memories." He spun around, pointing at Buffy. "That time when I helped you study for your maths exam, in Sunnydale. And the other time, when we stopped the Hellmouth opening while I taught you physics!" He grinned, rocking on his toes, hands clasped behind his back. "I remember that! Very clever. Doesn't quite top the driving lesson, but I thought it was a very close second."

Buffy shook her head, laughing. "What are you talking about?" She threw up her hands. "Look around you! This _is_ Sunnydale!"

"This is a cage," the Doctor countered. "A trap. A prison. I'm trapped in here, moved out of the way — my memory stifled and my mind…!"

As if from nowhere, a hypercube appeared on the table in the center of the library.

"Oh!" The Doctor darted over, picking it up. "Now, this is interesting. What are you doing here?"

Before he could open it or get a chance to see what was inside, he found himself elbowed out of the way as someone snatched the hypercube from his hands. The Doctor stumbled back, nearly falling — but Buffy caught him before he hit the ground.

"Angel!" Buffy complained at the blur that had knocked the Doctor down. "What did you do that for?"

Angel turned around. The light from the hypercube glowed upon his face like moonlight. "Buffy, you're losing control. Please, for the sake of everything, you have to pull yourself together. You must end this."

The Doctor stepped forwards, unconcerned. "Interesting that _you_ would turn up, Angel. After all, you kept a cube from me, once before — and it didn't exactly end well." He held out his hand, expectantly. "So! Give it back, and no hard feelings!"

Angel didn't.

Buffy stormed over, and yanked it out of Angel's hands, then gave it back to the Doctor.

"Thank you!" The Doctor grinned, and opened the message. The moment he heard it, the grin fell off his face.

 _"Mom… please… help me! I don't know how much longer I can do this." Seo was breathless, like she'd been running for hours. Her every word was a whisper, as if she were hiding. "Jenny brought one onto the TARDIS, but it multiplied. It took over the ship. It got Jenny. Then it got Father. I did something to the TARDIS, I hurt them, but Father's just… he's… his mind's…"_

 _Worry and terror flooded through the message._

 _"They know I'm the Key. They want to use that. They want to rip apart my mind. Please, Mom — I don't know who else to turn to. I don't know what else to do. I'm just hoping I can send this to somewhere you can get it, and then I'll make you a temporal portal to bring you into the TARDIS. You're my last hope, Mom. Save us."_

The Doctor dropped the hypercube on the ground. He could see more lizards skittering across bookcases, the floor to the library, the book cage — and Buffy and Angel rushed out to destroy them.

But the message… and the lizards…

"The Amansafari," the Doctor remembered. The entire world was shaking, around him. "They shattered my mental defenses. Destroyed my mind. I thought that was it — that they'd swallow me whole, along with everyone I'd ever met, or ever could meet. But then… then…"

The Doctor's eyes remained fixed on the hypercube.

Seo had saved him. Saved his companions.

And doomed the multiverse.

The Doctor heard a click, from behind him, of someone disengaging the safety on a handgun. Raising his hands, he turned around, slowly.

"Mom!" Buffy cried, racing in between the Doctor and the gun. "Stop it! What are you doing?"

"I don't think that's your mum, actually," the Doctor said. He stuck his hands into his coat pockets. "But I know why she turned up, here, in the guise of a mum. That much is obvious." He raised his eyebrows. "Hello, again — Buffy. Nice mind you've got, here."

Joyce didn't lower the gun.

"I imagine," the Doctor continued, "that when you found me, my fight against the Amansafari had left my mental defenses practically nonexistent. I was dying. Seo was weak and terrified and possibly no longer in her right mind. Jenny… well, she got taken over first, didn't she? By the time you turned up, the TARDIS must have looked like a disaster site."

Joyce took a long, shaky breath.

Then, in a very small voice, "The TARDIS… helped me, I think. I figured out what I had to do."

"She reconfigured the rooms so you'd wind up in the one with all the coronets," the Doctor guessed. He gave a small grin. "Course she did! And that room has a nice little diagram showing how to wire them all into the central console."

Joyce kept her face blank.

"And once your mind was linked to the TARDIS," the Doctor reasoned, "you brought us all back to Earth — to drop your daughter off with Alison! And when you realized that Seo and Jenny would have their memories partially wiped, as a result of this whole incident, you convinced the TARDIS to create you a nice little avatar, so Alison would know exactly what to do."

"I killed all the Amansafari onboard your ship," Joyce said. "But they sent more." She shuddered. "I didn't think they'd send for reinforcements so quickly. I thought I'd have more time."

The Doctor stepped forwards, placing his hands around Joyce's — on the gun.

"Buffy — listen to me," the Doctor told her, meeting her eyes with his. "Slayer or no — your brain is human. You can't shield me forever. It's too much. It'll kill you."

Joyce tried to blink back tears. Her eyes fell on the younger Buffy. "These days, with you, in Sunnydale — they were some of the happiest days of my life. My 18th birthday, with the stars. That time with the Facksisil of Balime, when you wouldn't stop licking me. The driving lessons. The slay-study sessions." She gave a small, heartbroken laugh. "That time when you replaced the wooden stake in my hand with a banana, and I looked like a total idiot, squishing it onto a vampire's shirt."

The Doctor gave a small laugh.

"All the times you believed in me," Joyce continued, "even when no one else thought I was smart or clever. Every time you reminded me that I was more than just 'the Slayer' or 'she who hangs out a lot in cemeteries'. And just… all those little moments. You know? Times when I was alone, and then you came, and I wasn't, anymore."

"Buffy…" the Doctor said.

"They need your brain, Doctor," Joyce told him. "Don't you understand? The only things stopping the Amansafari from getting the Key are Glory and the cyberplanner. And you're the one person, in the whole universe, who's defeated both."

The Doctor tried to adjust his bow tie… then realized he didn't have one.

"I can't let them get that information," Joyce said. "I'm the Slayer. I have a duty to something greater than myself."

Giles appeared, as if from nowhere. "In every generation, there shall be a chosen one. One girl, in all the world, to battle back the forces of darkness." He stood directly behind Joyce. "You can't delay this forever. He remembers, now. You must go through with it."

Joyce said nothing.

She didn't move.

"You're stalling them, outside, so you have time to do this, in here," Giles reminded her. "You can't stall them forever. You have to end this."

The Doctor looked between Giles and Joyce. "I see. So that's it."

Joyce remained silent.

"You _know_ it's killing you, trapping me inside your mind," the Doctor said. "You're banking on it. You're planning to crush me down — killing the both of us in an instant. That way, the Amansafari never get the information they need to destroy the multiverse."

Joyce still said nothing.

"Makes sense," the Doctor reasoned. He grinned. "Course it does! I'm on my last regeneration — end of the line, anyways! And you — well, you've been through a healthy dose of Watchers Council brainwashing, yourself. You'd gladly kill yourself for the multiverse."

Joyce's eyes narrowed. "It's not brainwashing. It's my duty."

"Yep, that's the brainwashing at work," the Doctor said. He regarded the gun in Joyce's hands. "You've been trying to kill me for a while, now. Haven't you? Every time you've shot me, you thought you'd go through with it. But you couldn't, in the end. Instead, you kept healing me — kept saving my life."

A tear rolled down Joyce's cheek.

The Doctor stepped towards her. "Thing is, Buffy — you can't jump into the portal every single time. Sometimes, you have to trust others to do it for you."

Giles cleared his throat, from behind the Doctor. "This is your destiny, Buffy."

"Giles is right; it's my life," Joyce said to the Doctor. "My choice."

For a few seconds, there was silence.

"But… what about me?" came a small voice, from behind the Doctor.

The Doctor spun around, to discover the far younger, 18-year-old Buffy, looking on at the others with horror-filled eyes.

"You can shut up," said Joyce. "You don't have any idea…"

The Doctor, however, swung an arm around the younger Buffy. "Actually, I think she deserves to speak." He beamed at her. "After all, she's a part of you — that little voice, deep down inside, that wants to live. Wants to trust. And is willing to let me go."

"She doesn't get any say!" Joyce shouted. "Look at her! She's a kid! A whiny, selfish little…!"

Younger Buffy lunged for Joyce, and the Doctor had to run in between them to stop the two of them from getting into a serious Slayer-style fight.

Younger Buffy pointed at Joyce. "I ran away. One summer — just one single summer — I ran away. And after that, my mom was so scared, she practically chained me to the house! That wasn't fair!"

"No, it wasn't fair — to _Mom_!" Joyce shouted. "You left Mom alone, scared to death that something had happened to you, and without any way to know you were okay! Do you have any idea what it's like to realize your daughter may never be coming back?!" Her eyes fell on the hypercube. "It breaks my heart, every time she goes away… because there's a part of me that's terrified I'll never see her, again."

"You're the Buffy who had those sick, twisted dreams, in 2004, about chaining the Doctor up and refusing to let him leave!" said the younger Buffy. "Do you get how creepy that is?" She threw open her arms. "This is a cage! This is evil! You've gotta let him go!"

"You're just saying that because you don't have the guts to sacrifice yourself to save your daughter!" Joyce shouted, actually dropping the gun to her side. She stormed over to Buffy. "You don't care that she's going to die, as long as _you_ find a way to survive." She gestured at the Doctor. "If I let him go, now — he's surrounded by Amansafari! They'll…"

"Then he'll have a plan!" Buffy shouted back at her. "He always has a plan! I trust him." She put her hands on her hips. "You guys always boss me around, in here. With your 'destiny' thing and your 'duty' stuff. But — you know what?" Buffy threw her stake away. "I don't want to be the Slayer. I don't want to be responsible. I just want to live."

The Doctor beamed at her. "And, you know what? That's brilliant." He turned to Joyce. "Isn't that brilliant, More-Responsible Buffy?"

Joyce said nothing.

"I've said it a thousand times," the Doctor told her, "and I'll keep saying it, until it sinks in. Buffy Anne Summers — you have to let me go."


	18. Chapter 18

**The TARDIS**

"You will give us the Time Lord, Slayer!" the Amansafari demanded. "Give us access to the Key!"

The image of Buffy Summers faded, as the real Buffy — from her spot on the floor — gave a cry of pain. She tried to struggle, her hands going up to her head and clutching the coronet, her feet kicking out against nothing, her breathing ragged and sparse.

"She's dying," Seo realized. She finally managed to break free from Jenny, and raced over to Buffy, kneeling beside her and reaching out for her. Tears fell from her eyes, as she tried, desperately, to help the mother she loved.

The Amansafari encircled Seo and Buffy, in a matter of moments. Their eyes bore down on Seo with a ravenous greed, and some were barely holding themselves back from swooping her up and chomping down on her right this second — Glory and cyberplanner be damned.

"Surrender the Key to us — without cyberplanner or Hell Goddess," the Amansafari demanded of Seo, "and we'll let your mother live." Their eyes flicked over to the Doctor. "The Time Lord, too."

Seo felt her hands shaking. She looked over her shoulder — at Jenny, whose eyes were still blank. "And Jenny?"

"We will spare all those closest to you," the Amansafari told her. They kept circling her, breathing her in like she was a pot roast. "Just give us the Key."

"But… but… it's not stable!" Seo insisted. "You can't use it!"

The Amansafari gave a screeching, high-pitched laugh. "The potential is all we need to feed. If you _can_ open the doors to the multiverse, then we can feed on the multiverse. You do not need to actually _open_ anything!"

One of them lunged for her, its gooey mouth forming razor sharp teeth, its tongue flicking out to taste the power she held. Another grabbed her other hand, trying to yank her in the other direction.

A third tore at her shirt, dragging her backwards and taking a long, hungry sniff.

Then all the others darted in, grabbing for her, licking her, sneering as they sized her up, allowing the deliciousness of their future feast to linger in their nostrils and expand within their imaginations.

Seo screamed.

On the floor, Buffy opened her eyes.

In two seconds, she'd flipped onto her feet, yanked the coronet off her head, and jammed the pointy end into one of the Amansafari's midsections. She kicked out at another one, slamming it away from her daughter and barreling into three others, behind it.

They all gave a high-pitched shriek, as they turned to her. "Slayer!"

"Hey, look at that! You brought an army!" Buffy punched one in the jaw, and grabbed up another's arm, snapping it. "That's a relief. It's been a while since I found a villain that was properly scared of me. It's kind of an ego-trip. You know?"

The Amansafari, no longer caught off-guard, launched themselves at her, fighting back. They burst into swarms of lizards, then regrouped and reformed, punching and biting and tearing at her.

"She is weak!" they shouted, as they caught her making mistakes. "She nearly killed herself, protecting the Time Lord. She will be easy to destroy."

That was when one of them — on the outskirts of the army — paused, in the fight. Looked around himself, sniffing, and analyzing the ground. "Wait… where _is_ the Time Lord?"

There, on the floor, where the Doctor used to be… was an empty coronet.

And no Doctor.

"She's a distraction!" the Amansafari shouted at the others. He raised the empty coronet in his hands. "The Time Lord's escaped, you fools! That was her plan all along!"

The others looked up, as well.

They only just caught Alison Korjensky flipping them the bird, before she followed the tweed jacketed man into the back rooms of the TARDIS.

"Forget the Slayer!" the Amansafari shouted. He waved at the others. "Bring the Key with us and get the Time Lord! _Now_!"

* * *

"Alison Korjensky!" the Doctor cried. "Brilliant to see you, again! Just brilliant!" He yanked her behind him, as she slowed a bit to look over her shoulder. "Don't stop running. Seo kicked them out of the ship's telepathic circuits, and Buffy's mind has been successfully keeping them out, so they'll have to catch me in person if they want to invade my mind. No more symbiotic links." They rounded a corner in the hallways. "Thank you for getting that nasty little coronet off my head. Coronets aren't cool, you know. Fezzes are cool." He clapped, overjoyed, as he thought of something. "Yes! Matrix Fez! That has to become a thing."

Alison glanced back over her shoulder, again. "You realize lizard-mania is on our heels?"

"Yes, yes, and yes!" the Doctor yanked her around a corner, buzzing a door with his sonic and sealing it shut. Then he glanced at her. "Oh, I nearly forgot!" He pointed at her. "Harald Gorm — importance to Viking History. Go!"

Alison gaped. "Sorry?!"

"Buffy asked me to quiz you on Viking history," the Doctor said, with a skip in his step. "Harald Gorm, also known as Harold Bluetooth. Met him, once, you know. Lovely fellow. Well, I say lovely. Bloodthirsty and obnoxious. But still! Lovely fellow!"

Then he turned, and yanked her behind him, as the sealed door burst inwards and the Amansafari army charged after them.

"As I told her," Alison hissed, while running, "now isn't the time for…!"

"Nonsense! No better time. You know, I taught Buffy maths while she was fighting off a Vexilothromin demon!" The Doctor grinned. "And this other time, a cadre of vampires decided to open the Hellmouth, and I taught her all the ins and outs of Maxwell's Equations and Einstein's theory of relativity, whilst we were stopping them."

A cluster of lizards flew through the air, striking the wall next to Alison. She shrieked, but the Doctor dragged her alongside, buzzing the next door shut.

"Right, so — it's not just Buffy who's mad," Alison decided. "It's all of you." Then, with a little laugh and a smile, added, "Now I know where Seo gets it from."

The Doctor leapt down a flight of stairs that Alison hadn't even seen, beforehand. She tumbled down them, dragged after him — scraping her knee a bit. She bit her lower lip, sucked up the pain, and forced herself onwards.

"I take it you do have a plan?" Alison asked.

The Doctor beamed. "Aha! Course I do! Sort of. Well, who's splitting hairs? I'm certainly not. So — yes! I have a plan!"

Yep.

Whole family was completely mad.

Alison just really, really hoped they'd all make it out of this one alive.


	19. Chapter 19

**The TARDIS**

Jenny jumped, like a zap of electricity had raced through her. She spun around herself, realizing she was in the console room of the TARDIS — alone, save for…

"Buffy Summers?!" Jenny cried.

Buffy slid the coronet off Jenny's head. "Yeah, I'm as surprised as you. One minute, it's 'not cool' to time travel with your mom, and the next, I'm getting panicked messages asking me to drop everything and run across space and time for her." She rapped her knuckles against the central console. "First things first. I need this thing to leap about 45 minutes into the future."

Jenny frowned. "Why…?"

Buffy just rapped her knuckles against the central console, again — expectantly.

Jenny sighed, then darted over to the console. "All right! All right! Fine. I'll do it." She pulled down the dematerialization lever, and the TARDIS wheezed and groaned — once — then pinged back into a landing.

Buffy grinned.

Raced over to the doors. Threw them open.

There, outside the TARDIS doors, was a street in Oxford, filled with traffic and noise and bustling with people. It looked the way it was supposed to look.

No more zombies — well, naturally, those had been a side effect of Buffy not really knowing how to use the TARDIS correctly, when she used it to shield the Doctor's mind. When Buffy created a projection of herself, to wander about in the real world and find Alison, the TARDIS had picked up on her stray thoughts, sent out a panicked psychic signal to the town, and then created tangible projections of all her friends from Sunnydale. And because Buffy's brain wasn't big and Time Lordy, her friends wound up not really being fleshed out or living — they were just kind of empty and shuffling.

But now, Buffy was awake. So it was all back to normal!

"Why are we…?" Jenny asked.

Buffy gestured out the doors. "To meet up with him."

One man, with glasses and gray hair and a ridiculously large bag of books, was running over to them at full pelt.

"Hey, Giles," Buffy said, as he ran inside. "Guess that means you got my message."

Giles panted, dropping his books to the floor. "Yes. And I spoke to Alison. I've been ringing people, on the drive over, asking about silver lizards and curses and such, and I've acquired a basic… theory…"

Giles trailed off, as he looked about himself, and realized where he was.

"Good Lord," Giles said, staring at the gigantic interior of the TARDIS. He took off his glasses, cleaned them, then placed them back on his face — as if this would make the illusion go away. It didn't. "Is it really…?"

Buffy bent down and grabbed one of the books. "Trust you to have the least exciting reaction to it, ever."

Giles blinked, squinting at the expansive dimensions, utterly enraptured. "I must say, that is… quite, quite extraordinary."

"Not extraordinary at all — it's basic dimensional transcendentalism," Jenny provided, running over. She grinned at him. "Bigger on the inside. It's easy, if you know how."

Buffy poked Giles with the book. "So, uh… lizard things?"

Giles blinked, again. Then tore his eyes away from the impossible ship around him, and returned them to Buffy. "Yes. Yes! Sorry. I… well…" He grabbed up a book, from his bag, flipping through it. "I rang Angel, back in the States, whilst driving."

"And Angel knew a guy who knew a demon who knew a guy who knew an alien?" Buffy guessed.

"Something like that." Giles found the page he wanted, and showed it to Buffy. "The Amansafari are a rather nasty group of mythical monsters who emerged, back in the 18th century, from the Australian Hellmouth." He pointed to the text. "It says here that the Slayer vanquished them by 'using an aborigeonese spell to project the essence of the Hellmouth directly into the Amansafari's minds'."

Buffy took the book from him, studying the passage, herself.

"Although, unfortunately," Giles muttered, turning away to find himself another book, "none of my books include the full written spell."

"Yeah, I thought you were going to go more with the 'unfortunately, Oxford doesn't have a Hellmouth' line," Buffy pointed out. She flipped the page, checking to see if there was anything else. Then sighed, and tossed the book back into the bag. "Okay. So much for plan A. Who's got a plan B?"

Jenny caught the book, before it landed. "Did you say… _dimensional_ energy? Same energy as Seo has?" She gestured at the back of the TARDIS. "But if their weakness is dimensional energy… then why do they want Seo?"

Buffy and Giles looked at one another.

Then Buffy began to grin.

"That's how she weakened them, the first time — so they _could_ go all death-by-hatstand!" Buffy realized. "It's why they don't care that Seo's unstable. If Seo actually _opens_ a portal, for any reason — that hurts them. But the _potential_ to open a portal allows them to feed!"

Buffy turned Jenny around, and shoved her back to the central console.

"Where…?" Jenny asked, confused.

"A Charitable Earth!" Buffy cried. She was grinning ear-to-ear, now. "I need to borrow my sister."

* * *

 **A Charitable Earth**

"Hello, this is a Charitable Earth. How can I help you?" Ace asked, using her nicest phone-voice. She paused. "Yes, I can assure you, all donations will be used towards the best possible cause, and will, in no way, be used to buy lots of nitro-9 or Dalek-killing super-weapons."

Ace paused, again.

Then looked up, from the phone.

"Of all the nerve!" Ace said. She pointed at it. "They hung up on me!"

Dawn sighed. "Okay, if we're going to make this work," she decided, "we've _got_ to do something about the sales pitch." Then she noticed Donna, sitting about and staring off into space. Dawn frowned, and leaned down, beside her. "Donna? You okay?"

Donna had been sketching something, idly, on the paper in front of her. It appeared to be a really weird-looking lizard, and some strange words above it.

Donna blinked, and snapped out of it. "What?" She turned back to the computer. "Yeah! Fine! Fine!" She gestured at the empty office, around them. "Just… is this what all new charities are like? Lots of furniture but nothing to do?" She gestured at the filing cabinet — empty. "There isn't even anything to bloomin' file, yet! How can you start a charity without any paperwork?!"

Dawn and Ace exchanged a look.

"Uh… actually… now that I think about it…" Ace grimaced.

"We were supposed to fill out a ton of paperwork before we actually rented the office, huh?" Dawn winced. "Okay, yeah. We definitely should have researched this better, before we founded it."

"Well, good thing you have the fastest typist in Chiswick!" Donna said, with a grin, getting up from her desk. "And her dashing assistant — who will be happy to run all over bloody everywhere, finding the forms." She went into the office kitchen. "Oi! Shaun!"

A faint wheezing, groaning sound echoed through the office.

Ace and Dawn exchanged a look.

"Whose turn is it to distract Donna, again?" Dawn asked, trying to think back to the last time the Doctor had turned up out of nowhere. It had been a while ago!

Ace turned to head over to the kitchens. "You did it, last time. That means, this time — TARDIS is all yours, Key-Girl!"

Dawn grinned.

Then raced out of the office.


	20. Chapter 20

**The TARDIS**

Alison nearly toppled over — and the Doctor actually _did_ topple over. Alison had to react pretty quickly, to catch him.

"Whoa! TARDIS is moving!" the Doctor cried. He laughed. "Geronimo!"

Then raced off, yet again.

Alison began to get a queasy feeling in her stomach. "Oi! Doctor! Don't tell me we're the distraction — to lure those silver slurpies out of the console room and allow Buffy to do something clever?"

The Doctor winked at her, and kept running.

"Well, do you know what Buffy's doing, at least?" Alison asked, as she darted out after him. "I mean, if you're just planning to run about, not helping or anything…!"

The Doctor buzzed at something with his sonic screwdriver. "Not helping? Who said I wasn't helping?" He raised a finger in the air, as if sensing something. Then pointed, and ran in a different direction. "Yes! That-a-way! Perfect!" He surged forwards, a bounce in his step. "Meanwhile — changes to Viking culture following their conversion to Christianity! Go!"

"All right, all right! Fine! I'll play along," Alison sighed. "The Vikings… err… didn't like fish, anymore?"

The Doctor swung around, to face her — running backwards. "Fish?!"

"Except on Fridays," Alison put in, hastily.

The Doctor sighed, turned back to the front. "You didn't actually do any reading on this, did you?"

"Oi! I was planning to do it, today!" Alison shouted. "I wasn't expecting a bunch of lizard-aliens to skitter about and be evil!" She gestured at him. "If you're so clever, how 'bout _you_ tell _me_?"

So he did.

* * *

Dawn didn't know what was going on, as she was yanked into the TARDIS. All she heard was silver lizards, end of the universe, and Key energy.

"You know, Buffy," Dawn pointed out, as the doors were shut behind her, "back when I was 14, you promised me — after Glory's deadline, no more Key stuff. But here I am, still doing Key stuff. And I hang out with Glory's nearest equivalent — Seo — like, all the time. We do lunch at least once a month."

Buffy sighed. "Dawn, seriously, less with the exaggeration. Seo's got, like, _one_ drop of Glory in her. She's not a psycho…" Buffy trailed off. Then turned on Dawn. "Hang on. Seo has lunch with you once a month?!" She gritted her teeth. "I am totally giving that girl a piece of my mind for not even calling, once, this whole time!"

Giles cleared his throat. "Yes, well, as lovely as it is to see you, again, Dawn — and in this really…" He glanced out at it, again, as if he were afraid the illusion would vanish, "...rather extraordinary ship…" He gestured at Buffy. "I think it's about time that we did the spell."

"Yeah… about that," Buffy said. She looked over at the far door at the back of the console room. "We still don't know what the spell is. And I was sort of hoping the Doctor would come back in, right around now, to tell us what to do next — but I'm starting to think that's not happening."

Dawn dug around, in her pocket, and brought out Donna's sketch of the weird lizard. Above it were some lines of phonetics that definitely did not spell out normal English words.

"Uh… any chance this helps?" Dawn handed the paper over to Buffy. "Donna drew it. You know, during one of her… Doctor-moments."

Buffy and Giles just stared at it.

It was, of course, exactly what they needed.

* * *

"What is this place?" Alison asked, looking at the gothic room and the swirl of purple energy in the middle of it. She shuddered, just walking in. There was something… overpowering about this room. Something that made her feel small.

"Node manipulator room!" the Doctor cried. He ran over to a set of controls. "One of the few things I can really thank the Master for. He tried to kill me, here. That was brilliant!" He paused. Tapped his sonic against his chin. "No. Not brilliant. What word am I looking for? Oh, right!" He pointed the sonic at Alison. "Rubbish! That was rubbish!"

The door juddered, and the Doctor soniced it locked.

"Barricade that!" The Doctor wiggled his fingers, above the node manipulator controls. "I think it's time I was astonishingly clever!"

* * *

At first, it didn't seem to be working, at all.

They sat, in the circle, reciting words in a language they didn't know, burning incense and pouring out sand onto the TARDIS floor.

" _Gin-boro-n-ngana balangurrk nimbutj-ja gungarak_ ," said Giles, as he traced a pattern in the sand. " _Warkagany wulkguni, dowk-ga._ "

" _Weng mi-ma ngerre-ngana_ ," chanted the others, as Dawn blew the incense. " _Larp mi-walngaran_."

For a second, nothing.

Then, suddenly, a crackle of energy seemed to buzz across the TARDIS — coming from some back room of the TARDIS, perhaps where the Doctor was. And the console room began to glow a faint green.

" _Yurrh-ma larima yunbu-yan wutjbin_ ," Giles recited. " _Dam ba-ma-ny._ "

Dawn began to feel something deep down inside of her. She looked down at her hands — and they were glowing with a powerful green energy. Her whole body was glowing.

A gong sounded in the TARDIS.

And somewhere, deep down inside it, the universe ripped apart.

* * *

Seo struggled to break free from the Amansafari, as they raced after the Doctor. She struggled to even just make them a little bit slower in their chase — but she could feel them pressing down, inside her mind. They were trying to drill holes into it, dig down deep, deep inside of her…

Seo screamed.

She could remember them doing this, before! She had struggled, clawed against them, fought and kicked and finally managed to push them out. But they weren't taking no for an answer, this time. They were determined to get at the Key, and they were prepared to tear her mind to shreds, to do so.

Just like she'd watched them do to the Doctor.

Oh… God…

She could see them stopping. She could see them banging on a door, trying to break it down. Another one of the crowd broke apart, coming towards her, his eyes staring and hungry. He grabbed her by the arm, dragging her forwards.

"Key," he hissed, flicking out his tongue and licking the side of her face. He gave a chirrup of orgasmic satisfaction. "So tasty."

Seo tried to break his pinky finger, but he stabbed into her mind, again, and she drew herself into a ball, shielding her mind from his attacks. She desperately clung to her sanity. She couldn't let them destroy her like they'd destroyed the Doctor. She wouldn't!

His teeth flashed, as he opened his mouth — deciding he didn't care about the risks, he was going to start munching on her, early — when suddenly…

The gong sounded.

Seo felt something tear apart, elsewhere in the TARDIS. She felt energy surge through her, as her skin glowed a bright and powerful green.

Around her, the Amansafari howled, grabbing their heads.

Seo realized — with relief! — that they were yanking themselves out of her mind, scrambling to find a way to abandon all contact with her. She was thrown to the ground, as they skittered away from her, still holding their heads in agony.

Seo groaned, pulling herself up off the ground and trying to forget just how much alien slobber she was coated in, at the moment.

The door opened.

"No, no, no, no, no!" the Doctor cried, running out the door and corridor for Seo. He spotted her, and rushed towards her. "Not the Jelly Stone! The Jelling Stones! _Jellingstenene_! Harold Bluetooth — told you! Very important."

He scanned Seo up and down with the sonic, to make sure she was fine. Then seemed to remember it gave no readings, and squinted at it, anyways, so he'd still look cool.

"I still remember the day he turned to me," the Doctor continued, studying the blank screwdriver, "and said, 'Doctor, tomorrow, we cross the Ravning Bridge. But today — we sing songs of the victory against the Sontarans!'"

Alison rolled her eyes. "Right. Course! I'll just write that into my paper — alongside all the bits about the Ione Hellmouth and the resurrected demonic remains of that boneless bloke." But she saw Seo, looking pretty all right, and ran over, swooping her into a great big hug.

And because it was Alison, she didn't even seem to mind the alien slobber.

"No, not Ione — _Lindisfarne_ is the one with the Hellmouth," the Doctor corrected. "Ione just has a smallish purple hedgehog alien named Clive." He adjusted his sonic screwdriver, then buzzed it against the TARDIS wall. "Well, then — almost done with the Amansafari. Just have one more terribly clever thing to do!"

Seo felt lightheaded, watching the world swim around her, as the dimensional tear… shifted. Then moved, and relocated.

"Hold on!" the Doctor shouted, placing his sonic in his mouth, and grabbing Alison with one hand and a door-handle in the other.

Alison clung to Seo.

Behind them, a huge dimensional portal tore through the hallway, sucking up all the Amansafari and dragging Alison, the Doctor, and Seo off their feet. They clung to one another, tightly, to avoid being sucked inside.

But Seo, still covered in slobber, could feel herself slipping… more and more…

Then, with a shriek from Alison, Seo finally lost her grip, tumbling through the air…

And smacked, hard, against the end of the hallway, as the portal sealed itself up.

Seo gritted her teeth, rubbing her head. "Ow."

"I knew it was going to do that!" the Doctor insisted, rushing over to her, and offering her a hand up. "Well, depending on your definition of the word 'knew' — which may possibly have to be expanded to include its logical antonym, but — I knew it was going to do that!"

Seo accepted his hand. "Next time," she told Alison, "I'll take the Viking-research, and you can take the disgusting brain-sucking aliens. Deal?"


	21. Chapter 21

Author's Note: And the end.

Hope you enjoyed this story!

I will be going on a brief hiatus, unfortunately, because I have not actually finished writing the next story. Sorry about that - life kind of exploded on me. So stay tuned; hopefully, it won't be long before I'm back.

* * *

"I think this is the part where I say, thank you for saving my life, healing my brain, and — most importantly — for deciding not to kill me, at the end of it," the Doctor said, as he and Buffy walked along the streets of Oxford, beneath the streetlamps.

Giles was packing his books back into his car, to head home. Alison had to go read up on Vikings and write her paper. And Seo, after cleaning herself up a bit, had decided that it was the solemn duty of herself and her sister to 'help' Alison with her studies — which probably meant 'distract Alison from studying' — thereby making it as difficult as humanly possible for Alison to get any actual writing done.

Which left Buffy and the Doctor here. Alone. Walking the streets of Oxford.

Buffy said nothing, for a little while, her eyes fixed on the road.

"When I fought the First," Buffy said, at last, "Giles told me — I changed. He said I got cold. He said, if I had to choose, again, between Dawn and the universe… I'd shove her into the portal."

The Doctor shuffled, a little awkwardly.

"It was like that, again, when I went through Hell," Buffy said. "Just going from place to place, over and over again, and watching as everyone — good, bad, demon, human — was murdered. Exterminated." She shuddered. "I had to raise an army. Train them. Give them hope. Give them strength. And I stood there and watched as every single one of them died. No survivors."

"No one but you," the Doctor offered.

Buffy shrugged. "So I got hard. I got… you know. Slayery." She sighed. "And… yeah. You can see where it led — locking you inside my head and almost killing you."

The Doctor said nothing. Just flipped his sonic screwdriver into the air and caught it, over and over again.

He was thinking about all the times he'd faced down Daleks. What it had done to him.

"I'll get over it, I guess," Buffy decided, with a shrug. "It won't be easy or anything, but… it'll happen. Especially with Seo being all with the bubbliness and the love of life. And even if this Seo doesn't like to stick around, that much — I get a lot of visits from future-Seos. I'm sure one of them will dig me out of it."

The Doctor caught the sonic, then waggled it at her. "You know — no one did ever clear you of that Watchers' Council brainwashing. Did they?"

Buffy blinked at him. "I… huh?"

"Just because some stuffy blokes in suits called you 'Slayer' and 'Soldier' and 'Vampire-Staker-In-Chief' — that doesn't mean you have to die for the planet," the Doctor said. He grinned. "I, for one, quite enjoy having you alive. And I'm sure plenty of others would agree with me."

Buffy shook her head, with a laugh, hugging her arms. "Doctor," she insisted, "that _is_ what it means. It's basically rule one of the Slayer handbook!"

The Doctor made a face. "Rules are rubbish!" Then, considering, added — "Unless you're a companion. Then: don't wander off! But otherwise… rules! Rubbish!"

Buffy looked down at the pavement, beneath their feet.

The streetlamps bathed it in yellow light.

"Really, though," the Doctor put in, shooting her a sad smile. "I said it to Seo, and I'll say it to you — it's not a crime to want to _live_ for the universe, instead of die for it."

Buffy sighed, kicking a pebble with her shoe. "Like I said — I'll get over this whole funk-thing. Eventually. I always do."

"Course you will," the Doctor said, tossing his sonic into the air and catching it, again. "Buffy the Brilliant. That's what I always say."

Buffy shot him a look, as if to point out that he'd never called her that at any time that she could remember.

"Oh, shut it," the Doctor sighed. He buzzed the nearby street lamp to stop it flickering, and it bathed them in bright light. Overhead, the stars were twinkling in the night sky.

Night.

No more vampires. No more Sunnydale. No more Torchwood. And far too many hostile aliens. The whole world had changed, around them, yet here they both were.

Buffy and the Doctor — and their stars, twinkling, overhead, to illuminate the darkness in their souls.

"It _was_ a bit fun, in the old days," the Doctor said. He snuck a smile at her. "Wasn't it?"

"In Sunnydale?" Buffy leaned back against a streetlamp — remembering summers of making up monsters, the hours and hours of Buffy trying to patrol and getting frustrated when the Doctor stole her stakes from out of her hands, all the crazy times when the Doctor had popped his head around her door and waved, and she'd dropped everything to save the world with him. Because she always would.

"When you were around," Buffy said, "then… yeah. It was."

She was going to say more, when Jenny and Seo sprung up, giggling and laughing, and started making noises about taking the console apart so they could finally fix that chameleon circuit.

"Don't you dare!" the Doctor said, waggling his finger at them. "My TARDIS likes being a police box! She doesn't need a fixed up chameleon anything!"

Jenny gave a long sigh. "Dad, it's about the quantum mechanics of the thing." She practically gave the eyeroll in her voice. "Obviously."

"We'll blow it up when we're done," Seo offered. "To break it, again."

Jenny turned on her, mildly irritated, and Seo ran back into the TARDIS. Jenny chased after her, yelling something.

The Doctor ran his hands down his face. "Kids. I swore I'd never do this again, after Nyssa, Tegan, and Adric."

Buffy gestured at the TARDIS. "You better get in there before they take the whole central console apart."

"A fifth time," the Doctor muttered, heading towards the ship. He stopped, with his hand on the door. Then turned back to Buffy. "You know — I still owe you a trip."

Buffy, at first, honestly didn't have any idea what he was talking about.

Then she realized…

Oh, yeah!

At the end of that whole year with Dawn and Glory and the portal, the Doctor said he'd take her with him. Wow, that had been a long time ago! Buffy had almost forgotten all about that.

"Yeah… that's probably not going to happen, though," Buffy admitted, hearing Seo and Jenny chattering, in the TARDIS. Buffy gestured at it. "Seo says I'm not 'cool.' So it's usually a big no-go on the whole time travel thing."

The Doctor shrugged. "Well… I can always drop these two off. They don't need to know."

Buffy stared at him. She felt a grin creeping up her face. "You're serious?"

"Serious? Of course I'm serious! When am I ever not serious?" The Doctor adjusted his bow tie. "Not going to promise it'll be as exciting as growing up on the mouth of hell, but — well, maybe we could get a few less hell bits, and a few more nice ones." He grinned at her. "What do you say?"

Buffy's face was practically glowing with anticipation. "I'd like that."

The Doctor opened his mouth, to say more — but was interrupted by a crash from inside his TARDIS. He sighed. "Just a second." Then yanked open the doors, and ran inside. "No, no, no! You do not hook that up to a dematerialization circuit, young lady! What happens next time Clara tries to bake a soufflé? I'll tell you what'll happen. It'll dematerialize, that's what'll happen!"

The Doctor popped his head out the door, and mouthed the words, 'gimme a few days'.

Then closed the door, and continued to shout, as he threw the dematerialization lever. Outside, Buffy stood back, watching as the ship dematerialized.

But not, she knew, for the final time.


End file.
